Drop non-carriable lights and empty stacks that aren't overriding anything

apps/openmw/mwworld/cellstore.cpp

@@ -277,15 +277,16 @@ namespace
                     return;
                 }
 
-            // Note: we preserve RefNum when picking up or dropping an item. So if this RefNum is not found
-            // in this cell in content files, it doesn't mean that the instance is invalid.
-            // But non-storable item are always stored in saves together with their original cell.
+            // Note: we preserve RefNum when picking up or dropping an item. This includes non-carriable lights 'picked
+            // up' through Lua. So if this RefNum is not found in this cell in content files, it doesn't mean that the
+            // instance is invalid. But non-storable item are always stored in saves together with their original cell.
             // If a non-storable item references a content file, but is not found in this content file,
-            // we should drop it.
-            if (!MWWorld::ContainerStore::isStorableType<T>())
+            // we should drop it. Likewise if this stack is empty.
+            if (!MWWorld::ContainerStore::isStorableType<T>() || !state.mCount)
             {
-                Log(Debug::Warning) << "Warning: Dropping reference to " << state.mRef.mRefID
-                                    << " (invalid content file link)";
+                if (state.mCount)
+                    Log(Debug::Warning) << "Warning: Dropping reference to " << state.mRef.mRefID
+                                        << " (invalid content file link)";
                 return;
             }
         }