diff --git a/src/libslic3r/Preset.cpp b/src/libslic3r/Preset.cpp
index 89b12e625f6..5b83c306f93 100644
--- a/src/libslic3r/Preset.cpp
+++ b/src/libslic3r/Preset.cpp
@@ -644,9 +644,13 @@ void Preset::save(DynamicPrintConfig* parent_config)
     // no filament_id which caused AMS sync to fall back to the parent's Generic ID.
     // Also generate a new ID if filament_id is inherited from the parent (== base_id).
     // This happens when a user preset is saved for the first time without having its own ID.
+    // A user preset needs its own filament_id if:
+    // - it has no filament_id at all, OR
+    // - its filament_id does not start with "P" (user preset IDs start with "P",
+    //   system IDs start with GFL/OGFL/GFA/etc.)
     bool needs_unique_filament_id = this->is_user() && !this->name.empty() &&
         this->type == Preset::TYPE_FILAMENT &&
-        (this->filament_id.empty() || (!this->base_id.empty() && this->filament_id == this->base_id));
+        (this->filament_id.empty() || this->filament_id.front() != 'P');
     if (needs_unique_filament_id) {
         boost::uuids::detail::md5 hash;
         boost::uuids::detail::md5::digest_type digest;