ah okay, yeah super annoying. Duplicating classes is SO hard to troubleshoot, and for that matter fix.
I did notice these two duplicate classes which may lead to the issue - worth cleaning these up in someway and seeing if that helps.
When you say you've tried the troubleshooting tips, I assume then you've done the turn off > refresh > turn on > refresh process? I've found this to work 99% of the time.