diff --git a/src/libslic3r/GCode/ToolOrdering.cpp b/src/libslic3r/GCode/ToolOrdering.cpp
index 97075079b5..a65892525f 100644
--- a/src/libslic3r/GCode/ToolOrdering.cpp
+++ b/src/libslic3r/GCode/ToolOrdering.cpp
@@ -104,7 +104,16 @@ bool internal_solid_infill_uses_sparse_filament(const PrintRegion &region, Extru
 bool use_base_infill_filament_impl(const LayerTools &layer_tools, const PrintRegion &region)
 {
     const PrintRegionConfig &config = region.config();
-    if (!config.enable_infill_filament_override.value)
+
+    // Keep legacy "Filament for Features" behavior: an explicit sparse infill
+    // filament choice (different from wall filament) is an override even if the
+    // dedicated toggle is missing or false in the loaded config.
+    const bool explicit_sparse_override =
+        config.sparse_infill_filament.value > 0 &&
+        config.wall_filament.value > 0 &&
+        config.sparse_infill_filament.value != config.wall_filament.value;
+
+    if (!config.enable_infill_filament_override.value && !explicit_sparse_override)
         return true;
     if (layer_tools.object_layer_count <= 0)
         return false;
diff --git a/src/libslic3r/PrintObject.cpp b/src/libslic3r/PrintObject.cpp
index 0351325995..3090cec41f 100644
--- a/src/libslic3r/PrintObject.cpp
+++ b/src/libslic3r/PrintObject.cpp
@@ -3578,7 +3578,8 @@ static void apply_to_print_region_config(PrintRegionConfig &out, const DynamicPr
         if (it->first != key_extruder)
             if (ConfigOption* my_opt = out.option(it->first, false); my_opt != nullptr) {
                 if (one_of(it->first, keys_extruders)) {
-                    // "Default" (0) clears explicit override for this scope and lets fallback apply.
+                    // "Default" (0) keeps any prior explicit feature override from parent scopes.
+                    // This lets object/part base filament be the default unless an explicit feature filament was chosen.
                     int extruder = static_cast<const ConfigOptionInt*>(it->second.get())->value;
                     if (extruder > 0) {
                         my_opt->setInt(extruder);
@@ -3588,13 +3589,6 @@ static void apply_to_print_region_config(PrintRegionConfig &out, const DynamicPr
                             feature_overrides.solid_infill_filament = true;
                         else if (it->first == "wall_filament")
                             feature_overrides.wall_filament = true;
-                    } else {
-                        if (it->first == "sparse_infill_filament")
-                            feature_overrides.sparse_infill_filament = false;
-                        else if (it->first == "solid_infill_filament")
-                            feature_overrides.solid_infill_filament = false;
-                        else if (it->first == "wall_filament")
-                            feature_overrides.wall_filament = false;
                     }
                 } else
                     my_opt->set(it->second.get());