Jevon:
Just a few more ideas (no guarantees). One issue could be that you are using AC15 with OSX10.10, so upgrading AC or going back to the OS that was current when AC15 was released are two (difficult and/or expensive) options.
You could try placing a Hotspot at a problematic door, deleting it, and placing a new (hopefully) working door in its place. You could also try Merging the problematic model file into a new blank working template file, but this will transfer only the model, any 2D/annotation would have to be copied separately.
There is no hidden setting, it looks like a bug in this file. Good luck.
David