OK, thanks for the status update.  For my current example:

1. full_class_checking = False  (so that's not the problem here)
2. We do not use any qualified anchored types as far as I know, only
   normal anchored types.

I will try to reproduce on a reasonable size example and if I do, I will
upload it here so that you have a test case when your improved incrementality
code is ready.