source/blender/blenkernel/BKE_main.hh

@@ -191,6 +191,11 @@ struct Main {
    */
   bool is_global_main;
 
+  /**
+   * True if main used to store weakly referenced assets.
+   */
+  bool is_asset_weak_reference_main;
+
   BlendThumbnail *blen_thumb;
 
   Library *curlib;

source/blender/blenkernel/intern/asset_weak_reference.cc

@@ -144,6 +144,7 @@ struct AssetWeakReferenceMain {
   AssetWeakReferenceMain(std::string filepath)
       : filepath(std::move(filepath)), main(BKE_main_new())
   {
+    main->is_asset_weak_reference_main = true;
   }
   AssetWeakReferenceMain(const AssetWeakReferenceMain &) = delete;
   AssetWeakReferenceMain(AssetWeakReferenceMain &&other)

source/blender/blenkernel/intern/lib_id.cc

@@ -1269,6 +1269,9 @@ void *BKE_libblock_alloc(Main *bmain, short type, const char *name, const int fl
       if ((flag & LIB_ID_CREATE_NO_DEG_TAG) == 0) {
         DEG_id_type_tag(bmain, type);
       }
+      if (bmain->is_asset_weak_reference_main) {
+        id->tag |= LIB_TAG_ASSET_MAIN;
+      }
     }
     else {
       BLI_strncpy(id->name + 2, name, sizeof(id->name) - 2);
@@ -1462,6 +1465,10 @@ void BKE_libblock_copy_ex(Main *bmain, const ID *id, ID **r_newid, const int ori
     DEG_id_type_tag(bmain, GS(new_id->name));
   }
 
+  if (bmain && bmain->is_asset_weak_reference_main) {
+    new_id->tag |= LIB_TAG_ASSET_MAIN;
+  }
+
   *r_newid = new_id;
 }
 

source/blender/makesdna/DNA_ID.h

@@ -1006,7 +1006,7 @@ enum {
    * Datablocks like this can not be linked to and from datablocks in regular main.
    * They should stay isolated from each other.
    */
-  LIB_TAG_ASSET_MAIN = 1 << 20,
+  LIB_TAG_ASSET_MAIN = 1 << 27,
 
   /* ------------------------------------------------------------------------------------------- */