Bug Editor Warning: Calling Deallocate on pointer, that can not be deallocated....

There may be numerous deallocate issues, but I often see a warning in the editor, simply appearing after stopping my game running. It comes after a lightmap line in the log (I use no lightmaps!!) and an unloading one. 2019.4

Code (CSharp):

1.  
2. LightmapEditorSettings: switching bake backend from 1 to 0.
3. Unloading 12 Unused Serialized files (Serialized files now loaded: 0)
4. Calling Deallocate on pointer, that can not be deallocated by allocator ALLOC_TEMP_THREAD
5. (Filename: C:\buildslave\unity\build\Runtime/Allocator/StackAllocator.cpp Line: 160)
6.  

If this is a harmless warning then maybe remove it?!