diff --git a/src/libslic3r/PrintConfig.cpp b/src/libslic3r/PrintConfig.cpp
index 4c27995ba0..e8ac749bd3 100644
--- a/src/libslic3r/PrintConfig.cpp
+++ b/src/libslic3r/PrintConfig.cpp
@@ -10936,6 +10936,28 @@ std::vector<int> DynamicPrintConfig::update_values_to_printer_extruders(DynamicP
     return variant_index;
 }
 
+// Regathers a vector option's values through per-slot source indices (one input index per
+// output slot). Out-of-range indices keep the first value, matching get_at's fallback.
+template<typename OptType, typename ValueType>
+static void gather_option_values(const char *caller, const std::string &key, OptType *opt, const std::vector<int> &slot_param_indices)
+{
+    if (!opt || opt->values.empty()) {
+        BOOST_LOG_TRIVIAL(warning) << caller << boost::format(", Line %1%: option %2% not found or empty, skipping")%__LINE__%key;
+        return;
+    }
+    std::vector<ValueType> new_values;
+    new_values.reserve(slot_param_indices.size());
+    for (int idx : slot_param_indices) {
+        if (idx < 0 || static_cast<size_t>(idx) >= opt->values.size()) {
+            BOOST_LOG_TRIVIAL(warning) << caller << boost::format(", Line %1%: option %2% slot index %3% out of range, keeping first value")%__LINE__%key%idx;
+            new_values.emplace_back(opt->values.front());
+        }
+        else
+            new_values.emplace_back(opt->values[idx]);
+    }
+    opt->values = std::move(new_values);
+}
+
 void DynamicPrintConfig::update_values_to_printer_extruders_for_multiple_filaments(DynamicPrintConfig& printer_config, int extruder_count, int extruder_nozzle_volume_count, std::set<std::string>& key_set, std::string id_name, std::string variant_name)
 {
     BOOST_LOG_TRIVIAL(info) << __FUNCTION__ << boost::format(", Line %1%: extruder_count %2%, extruder_nozzle_volume_count %3%")%__LINE__ %extruder_count %extruder_nozzle_volume_count;
@@ -11013,155 +11035,18 @@ void DynamicPrintConfig::update_values_to_printer_extruders_for_multiple_filamen
                 BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: can not find opt define for %2%")%__LINE__%key;
                 continue;
             }
+            // An empty option has no first value to fall back on; give it one registered default per filament.
+            if (auto *vec = dynamic_cast<ConfigOptionVectorBase*>(this->option(key)); vec && vec->empty() && optdef->default_value)
+                vec->resize(filament_count, optdef->default_value.get());
 
             switch (optdef->type) {
-                case coStrings:
-                {
-                    ConfigOptionStrings * opt = this->option<ConfigOptionStrings>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<std::string> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coInts:
-                {
-                    ConfigOptionInts * opt = this->option<ConfigOptionInts>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<int> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coFloats:
-                {
-                    ConfigOptionFloats * opt = this->option<ConfigOptionFloats>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<double> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coPercents:
-                {
-                    ConfigOptionPercents * opt = this->option<ConfigOptionPercents>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<double> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coFloatsOrPercents:
-                {
-                    ConfigOptionFloatsOrPercents * opt = this->option<ConfigOptionFloatsOrPercents>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<FloatOrPercent> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coBools:
-                {
-                    ConfigOptionBools * opt = this->option<ConfigOptionBools>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<unsigned char> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
-                case coEnums:
-                {
-                    ConfigOptionEnumsGeneric * opt = this->option<ConfigOptionEnumsGeneric>(key);
-                    if (!opt) {
-                        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found, skipping")%__LINE__%key;
-                        break;
-                    }
-                    std::vector<int> new_values;
-
-                    new_values.resize(filament_count);
-                    for (int f_index = 0; f_index < filament_count; f_index++)
-                    {
-                        if (variant_index[f_index] < 0 || static_cast<size_t>(variant_index[f_index]) >= opt->size()) {
-                            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% variant index %3% out of range, skipping")%__LINE__%key%variant_index[f_index];
-                            continue;
-                        }
-                        new_values[f_index] = opt->get_at(variant_index[f_index]);
-                    }
-                    opt->values = new_values;
-                    break;
-                }
+                case coStrings:          gather_option_values<ConfigOptionStrings, std::string>(__FUNCTION__, key, this->option<ConfigOptionStrings>(key), variant_index); break;
+                case coInts:             gather_option_values<ConfigOptionInts, int>(__FUNCTION__, key, this->option<ConfigOptionInts>(key), variant_index); break;
+                case coFloats:           gather_option_values<ConfigOptionFloats, double>(__FUNCTION__, key, this->option<ConfigOptionFloats>(key), variant_index); break;
+                case coPercents:         gather_option_values<ConfigOptionPercents, double>(__FUNCTION__, key, this->option<ConfigOptionPercents>(key), variant_index); break;
+                case coFloatsOrPercents: gather_option_values<ConfigOptionFloatsOrPercents, FloatOrPercent>(__FUNCTION__, key, this->option<ConfigOptionFloatsOrPercents>(key), variant_index); break;
+                case coBools:            gather_option_values<ConfigOptionBools, unsigned char>(__FUNCTION__, key, this->option<ConfigOptionBools>(key), variant_index); break;
+                case coEnums:            gather_option_values<ConfigOptionEnumsGeneric, int>(__FUNCTION__, key, this->option<ConfigOptionEnumsGeneric>(key), variant_index); break;
                 default:
                     BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: unsupported option type for %2%")%__LINE__%key;
                     break;
@@ -11180,28 +11065,6 @@ void DynamicPrintConfig::update_values_to_printer_extruders_for_multiple_filamen
     }
 }
 
-// Regathers a vector option's values through per-slot source indices (one input index per
-// output slot). Out-of-range indices keep the first value, matching get_at's fallback.
-template<typename OptType, typename ValueType>
-static void gather_option_values(const std::string &key, OptType *opt, const std::vector<int> &slot_param_indices)
-{
-    if (!opt || opt->values.empty()) {
-        BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% not found or empty, skipping")%__LINE__%key;
-        return;
-    }
-    std::vector<ValueType> new_values;
-    new_values.reserve(slot_param_indices.size());
-    for (int idx : slot_param_indices) {
-        if (idx < 0 || static_cast<size_t>(idx) >= opt->values.size()) {
-            BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: option %2% slot index %3% out of range, keeping first value")%__LINE__%key%idx;
-            new_values.emplace_back(opt->values.front());
-        }
-        else
-            new_values.emplace_back(opt->values[idx]);
-    }
-    opt->values = std::move(new_values);
-}
-
 void DynamicPrintConfig::update_filament_config_values_for_multiple_extruders(DynamicPrintConfig& printer_config,
     const std::unordered_map<int, std::vector<FilamentVariantUse>>& filament_variant_uses,
     int extruder_count, int extruder_nozzle_volume_count,
@@ -11296,13 +11159,13 @@ void DynamicPrintConfig::update_filament_config_values_for_multiple_extruders(Dy
             continue;
         }
         switch (optdef->type) {
-            case coStrings:          gather_option_values<ConfigOptionStrings, std::string>(key, this->option<ConfigOptionStrings>(key), slot_param_indices); break;
-            case coInts:             gather_option_values<ConfigOptionInts, int>(key, this->option<ConfigOptionInts>(key), slot_param_indices); break;
-            case coFloats:           gather_option_values<ConfigOptionFloats, double>(key, this->option<ConfigOptionFloats>(key), slot_param_indices); break;
-            case coPercents:         gather_option_values<ConfigOptionPercents, double>(key, this->option<ConfigOptionPercents>(key), slot_param_indices); break;
-            case coFloatsOrPercents: gather_option_values<ConfigOptionFloatsOrPercents, FloatOrPercent>(key, this->option<ConfigOptionFloatsOrPercents>(key), slot_param_indices); break;
-            case coBools:            gather_option_values<ConfigOptionBools, unsigned char>(key, this->option<ConfigOptionBools>(key), slot_param_indices); break;
-            case coEnums:            gather_option_values<ConfigOptionEnumsGeneric, int>(key, this->option<ConfigOptionEnumsGeneric>(key), slot_param_indices); break;
+            case coStrings:          gather_option_values<ConfigOptionStrings, std::string>(__FUNCTION__, key, this->option<ConfigOptionStrings>(key), slot_param_indices); break;
+            case coInts:             gather_option_values<ConfigOptionInts, int>(__FUNCTION__, key, this->option<ConfigOptionInts>(key), slot_param_indices); break;
+            case coFloats:           gather_option_values<ConfigOptionFloats, double>(__FUNCTION__, key, this->option<ConfigOptionFloats>(key), slot_param_indices); break;
+            case coPercents:         gather_option_values<ConfigOptionPercents, double>(__FUNCTION__, key, this->option<ConfigOptionPercents>(key), slot_param_indices); break;
+            case coFloatsOrPercents: gather_option_values<ConfigOptionFloatsOrPercents, FloatOrPercent>(__FUNCTION__, key, this->option<ConfigOptionFloatsOrPercents>(key), slot_param_indices); break;
+            case coBools:            gather_option_values<ConfigOptionBools, unsigned char>(__FUNCTION__, key, this->option<ConfigOptionBools>(key), slot_param_indices); break;
+            case coEnums:            gather_option_values<ConfigOptionEnumsGeneric, int>(__FUNCTION__, key, this->option<ConfigOptionEnumsGeneric>(key), slot_param_indices); break;
             default:
                 BOOST_LOG_TRIVIAL(warning) << __FUNCTION__ << boost::format(", Line %1%: unsupported option type for %2%")%__LINE__%key;
                 break;
diff --git a/tests/libslic3r/test_config_variant_expansion.cpp b/tests/libslic3r/test_config_variant_expansion.cpp
index 2469789d5b..d8e09539bb 100644
--- a/tests/libslic3r/test_config_variant_expansion.cpp
+++ b/tests/libslic3r/test_config_variant_expansion.cpp
@@ -484,6 +484,34 @@ TEST_CASE("update_values_to_printer_extruders_for_multiple_filaments resolves pe
         REQUIRE(config.option<ConfigOptionFloats>("filament_max_volumetric_speed")->values == std::vector<double>({12., 21.}));
         REQUIRE(config.option<ConfigOptionInts>("filament_self_index")->values == std::vector<int>({1, 2}));
     }
+
+    SECTION("a variant option shorter than the filament slots keeps its first value instead of zero") {
+        DynamicPrintConfig config;
+        config.option<ConfigOptionEnumsGeneric>("extruder_type", true)->values = {etDirectDrive, etDirectDrive};
+        config.option<ConfigOptionEnumsGeneric>("nozzle_volume_type", true)->values = {nvtStandard, nvtHighFlow};
+        config.option<ConfigOptionStrings>("extruder_variant_list", true)->values = {"Direct Drive Standard,Direct Drive High Flow",
+                                                                                     "Direct Drive Standard,Direct Drive High Flow"};
+        make_filament_arrays(config);
+        config.option<ConfigOptionInts>("filament_map", true)->values = {1, 2};
+        // no loaded preset carries the key, so only its single registered default is present
+        config.option<ConfigOptionFloatsNullable>("filament_cooling_before_tower", true)->values = {10.};
+        // only the first filament's two variant columns were loaded
+        config.option<ConfigOptionFloatsNullable>("filament_ramming_volumetric_speed", true)->values = {-1., -2.};
+
+        std::vector<std::vector<NozzleVolumeType>> nozzle_volume_types;
+        int extruder_count = 2;
+        int count = config.get_extruder_nozzle_volume_count(extruder_count, nozzle_volume_types);
+
+        config.update_values_to_printer_extruders_for_multiple_filaments(config, extruder_count, count, filament_keys,
+            "filament_self_index", "filament_extruder_variant");
+
+        // filament 2 resolves to column 3 (its extruder's High Flow column), past the end of both vectors
+        REQUIRE_THAT(config.option<ConfigOptionFloatsNullable>("filament_cooling_before_tower")->values,
+                     Catch::Matchers::Approx(std::vector<double>({10., 10.})));
+        REQUIRE_THAT(config.option<ConfigOptionFloatsNullable>("filament_ramming_volumetric_speed")->values,
+                     Catch::Matchers::Approx(std::vector<double>({-1., -1.})));
+        REQUIRE(config.option<ConfigOptionFloats>("filament_max_volumetric_speed")->values == std::vector<double>({12., 21.}));
+    }
 }
 
 // update_values_from_multi_to_multi_2 walks the DESTINATION PRINTER's variant list while writing