This problem is likely a showstopper for my project.

I just had the pleasure of it unhooking one very important pin from a struct. And it also just hosed my casters AOE healing action randomly. The file is still read only.

Can someone at least explain how a file that is read only is being modified by UE4?

This wasn’t a crash. I merely had to close the editor and open it again. I made sure everything was saved.