I gave the level another go on TSF+ and found that by playing all the way through without loading from a savegame makes it work. After the first door I did load from a save again though, and the 2nd door got messed up again. In that case, even moving away to the far corner of the level won't suffice somehow. Even dying and replaying from the checkpoint didn't work. I know this level had a chance to crash on vanilla, but I still don't see why it would affect crates in masks.

So can savefiles (even in nonplus based levels) somehow be related to this?

And is anyone else unable to activate the underwater trigger zone on vanilla TSF?