So i was making my mod and after some navmeshing i clicked 'save' and it crashed.
I was convinced it had something to do with navmeshing, but i was wrong.
There were 2 things i found that could make it crash on save:
1. Having a new music track assigned to a place or action WITHOUT A MUSIC FILE SELECTED (it de-selects the file each time you save, so you have to do it every time)
2. Having a magic effect without any actual magic effect, like an empty entry.
Not sure if this helps you, but when i deleted the music track from the list and the effectless magic, it got fixed.