My avatar is stuck on one level even though I've progressed about 50 levels ahead.

Sheila_English

Even though this works correctly on my phone, it doesn't on FB. I'm stuck forever on one level and have to re-play the others to get up to the level I need to be at. 

Tune_D

Logout of Facebook both on your phone as from within the game app itself. Check for updates for your phone and all apps and do a restart.

Open the game app again and connect it to your Facebook. I think this recent issue https://care.king.com/en/candy-crush-jelly-saga/jelly-crush-will-not-connect-to-facebook might have affected you too.