It looks like change in kerning or kerning groups first and then opening the kerning window causes Glyphs to crash. When the window is open all the time, it doesn’t happen. It seems that it fails to make a database of kerning needed for kerning window to function. Is it reported already?
I have experienced this myself, but was unaware of what was actually causing the problem. As Tosche suggested once you have the kerning window active after the crash it doesn’t happen.
I see the crash reports about this crash but can’t reproduce it. Tosche, if you can reproduce it reliably, could you make a screen recording of the crash?