Ah sorry, I see now.
I think I would now back up my profile folder and then uninstall Opera, and find and delete any remaining folders and files relating to it, including all the shortcuts. Cleaning the registry of all Opera entries would be a good idea too (back it up first of course!)
Then reinstall Opera and see if the problem is still there with a clean new profile.
If it is, I can only assume it's a problem between Opera Beta and Windows 10, which I would have thought others would be experiencing too.
If it fixes it I would assume that something had got corrupted with the Windows 10 update, for reasons unknown.
You can then delete the new profile and replace it with your saved one, and hope that doesn't bring the problem back!
If it doesn't, all should be well.
🙂