diff --git a/tests/libslic3r/test_preset_bundle_loading.cpp b/tests/libslic3r/test_preset_bundle_loading.cpp
index 5341e6c621..29c38395ac 100644
--- a/tests/libslic3r/test_preset_bundle_loading.cpp
+++ b/tests/libslic3r/test_preset_bundle_loading.cpp
@@ -1031,6 +1031,93 @@ TEST_CASE("Manifest-backed resolution reuses the vendor tree it already loaded",
     CHECK_THAT(travel_speed(fresh, "second.json"), Catch::Matchers::WithinAbs(222.0, 1e-6));
 }
 
+TEST_CASE("Manifest-backed resolution does not keep a vendor tree that failed to load", "[Preset][Bundle][Regression]")
+{
+    ScopedTemporaryDir dir;
+    const fs::path      child_file = dir.path() / "Acme" / "process" / "child.json";
+    auto write_manifest = [&](const std::string &leading_entry) {
+        std::ofstream((dir.path() / "Acme.json").string())
+            << R"({"version":"1.0.0","name":"Acme","process_list":[)" << leading_entry
+            << R"({"name":"Acme Process","sub_path":"process/child.json"}]})";
+    };
+    write_manifest("123,");
+    fs::create_directories(child_file.parent_path());
+    std::ofstream(child_file.string())
+        << R"({"type":"process","name":"Acme Process","from":"system",)"
+        << R"("instantiation":"true","layer_height":"0.2"})";
+
+    PresetBundle bundle;
+    auto resolve = [&](std::string &error) {
+        DynamicPrintConfig raw;
+        raw.option<ConfigOptionString>(BBL_JSON_KEY_INHERITS, true)->value = "fdm_process_common";
+        return bundle.resolve_preset_config(raw, Preset::TYPE_PRINT, child_file.string(),
+                                            ForwardCompatibilitySubstitutionRule::EnableSilent, error);
+    };
+
+    std::string error;
+    CHECK_FALSE(resolve(error));
+    CHECK_FALSE(error.empty());
+
+    write_manifest("");
+    error.clear();
+    CHECK(resolve(error));
+    CHECK(error.empty());
+}
+
+TEST_CASE("Manifest-backed resolution reuses the library base for type-probed files", "[Preset][Bundle][Regression]")
+{
+    ScopedTemporaryDir dir;
+    const fs::path      library_pet  = dir.path() / PresetBundle::ORCA_FILAMENT_LIBRARY / "filament" / "pet.json";
+    const fs::path      filament_dir = dir.path() / "Acme" / "filament";
+
+    std::ofstream((dir.path() / (std::string(PresetBundle::ORCA_FILAMENT_LIBRARY) + ".json")).string())
+        << R"({"version":"1.0.0","name":"OrcaFilamentLibrary","filament_list":[)"
+        << R"({"name":"fdm_filament_pet","sub_path":"filament/pet.json","filament_id":"GFL99"}]})";
+    fs::create_directories(library_pet.parent_path());
+    auto write_library_pet = [&](double density) {
+        std::ofstream(library_pet.string())
+            << R"({"type":"filament","name":"fdm_filament_pet","from":"system",)"
+            << R"("filament_id":"GFL99","instantiation":"false",)"
+            << R"("filament_type":["PETG"],"filament_density":[")" << density << R"("]})";
+    };
+    write_library_pet(1.27);
+
+    std::ofstream((dir.path() / "Acme.json").string())
+        << R"({"version":"1.0.0","name":"Acme","filament_list":[)"
+        << R"({"name":"Acme PETG","sub_path":"filament/petg.json","filament_id":"GFA00"},)"
+        << R"({"name":"Acme PETG Matte","sub_path":"filament/petg_matte.json","filament_id":"GFA01"}]})";
+    fs::create_directories(filament_dir);
+    auto write_child = [&](const std::string &file, const std::string &name, const std::string &filament_id) {
+        std::ofstream((filament_dir / file).string())
+            << R"({"type":"filament","name":")" << name << R"(","from":"system",)"
+            << R"("filament_id":")" << filament_id << R"(","instantiation":"true","inherits":"fdm_filament_pet"})";
+    };
+    write_child("petg.json", "Acme PETG", "GFA00");
+    write_child("petg_matte.json", "Acme PETG Matte", "GFA01");
+
+    auto density = [](const DynamicPrintConfig &config) {
+        return config.option<ConfigOptionFloats>("filament_density")->values.front();
+    };
+
+    PresetBundle       bundle;
+    DynamicPrintConfig first;
+    first.option<ConfigOptionString>(BBL_JSON_KEY_INHERITS, true)->value = "fdm_filament_pet";
+    std::string error;
+    REQUIRE(bundle.resolve_preset_config(first, Preset::TYPE_FILAMENT, (filament_dir / "petg.json").string(),
+                                         ForwardCompatibilitySubstitutionRule::EnableSilent, error));
+    CHECK_THAT(density(first), Catch::Matchers::WithinAbs(1.27, 1e-6));
+
+    // Only a reload would see this change.
+    write_library_pet(1.5);
+
+    DynamicPrintConfig second;
+    Preset::Type       type = Preset::TYPE_INVALID;
+    REQUIRE(bundle.resolve_preset_config_type(second, type, (filament_dir / "petg_matte.json").string(),
+                                              ForwardCompatibilitySubstitutionRule::EnableSilent, error));
+    CHECK(type == Preset::TYPE_FILAMENT);
+    CHECK_THAT(density(second), Catch::Matchers::WithinAbs(1.27, 1e-6));
+}
+
 // Orca: a filament in the Orca Filament Library that names its compatible printers has to hide the generic
 // library filament sharing its alias, the same way a vendor owned filament does. Otherwise both are compatible
 // with that printer and the plater combo box lists the shared alias twice.