Hello,
I also have the same issue with the latest Opera version (OS is Windows 8.1), which is 41. something (I'm at work, can't check it).
I had this issue for about 2 weeks now, I've tried to uninstalling it (deleting the opera folder also) and then reinstalling it, but still has the same issue.
The issue is whenever I try to delete a bookmark, it sometimes (let's say 5 out of 10 times) just freezes for 1-2 seconds, then crashing completely.