>>1290046I'm this guy
I replaced the cassette and the problem was solved.
New problem is my derailleur looks...wrong.
In some gear configurations the chain rubs on the cage around the jockey wheels.
Could the derailleur or the hanger be damaged? I don't recall it sustaining any hits. But it appears to be at a funky angle.
I can take it to the lbs but they charge money and are difficult to deal with sometimes.