Built up a new bike with my old components. On my original rear wheel I had a dork disk along with a thin metal spacer between it and the cassette. I trashed the dork disk but put the spacer in before my cassette. Did a very short 2.3 mile tune-up ride. Did a 17 mile tune-up ride. Weird shifting, maybe some extra noise going over cracks/bumps (chalked it up to going from a full carbon to 1/2 carbon 1/2 aluminum frame).

Checked my cassette and it was loose! Skewer was tight, lockring was pretty tight based on how hard I had to pull to get it off again. Took everything off, cleaned it out real good including the "10s" spacers. Put it all back on. Got it good-n-tight with my Park Tool stuff. Now there's no play.

Did I just not tighten the lockring down enough or is it possibly coming loose while I'm riding?? Do I need to put threadlocker in the lockring threads?