Actually, I was streaming when this happened, and it got captured on the VOD:
https://www.twitch.tv/videos/2150126761?t=00h30m05s
(skip to 30:05 if it doesn't do it automatically)
You can see the exact sequence of buttons I clicked to trigger the crash; and then I repeated that same series of commands and it crashed again. (Fortunately, thanks to autosave, I didn't lose my work!)
(Example sprite I made using bone animation, though it really only ended up necessary for the front leg)