Playlist: Don't automatically sort playlist before it's fully loaded

Fixes #1690

src/playlist/playlist.cpp

@@ -1205,7 +1205,7 @@ void Playlist::InsertItemsWithoutUndo(const PlaylistItemPtrList &items, const in
     queue_->InsertFirst(indexes);
   }
 
-  if (auto_sort_) {
+  if (auto_sort_ && !is_loading_) {
     sort(static_cast<int>(sort_column_), sort_order_);
   }