I've discovered a bug that we've been able to duplicate across different computers. The following steps consistently crash Storyline 2, Update9: 1605.1919. I see that there's a newer update but I didn't see this one addressed in the fixes for update 10.
- Insert > Controls > Radio buttons > (choose style 2)
- Add a label to the button by typing some text
- Click on the button/label to activate it as if you were going to move it