I just had the exact same problem (still unresolved!)
I was synching changes from my i-pad and now my entire library (12,000 cards) are showing in reverse.
Initially I suspended the Basic(and reversed) cards. Problem did not resolve.
I have deleted all the Basic(and reversed) cards, but the remaining cards do not revert to normal.
Am really worried that I won’t be able to restore normal format to these cards 
What do I do next ?
I made sure Anki is the newest edition/ dowload and reinstalled.
Any other suggestions?
Thanks…