1) I did check the content of level. It was valid, in fact, it was the exact same string as the previous level load function call got, around 5 minutes earlier.
2) Is also a valid point, but if the entity was removed, all of the functions which have it as a "my" pointer would have been stopped and the my pointer set to NULL, according to the manual and all other tests I have made.

I've included a link at the end of my post above to a post where we've already tried quite a few things regarding the ent_remove problem. I've done quite a bit of logging, and the only thing that I can think of now is that only part of the entity memory has been overwritten, because the entity does still exist.