Very odd. Sorry that it didn’t sort it for you. It has for me on 6 projects.
I was seeing something like this on my project. I had a window property that was set to an object instance.
The error would be triggered at application close time if at any point in time I changed that property to reference another object before setting it to nil first.
Ex:
// crashes
Window1.aProperty = newReference
// no crash
Window1.aProperty = Nil
Window1.aProperty = newReference
Hope it helps…