Kohler canister valve rotating

My Kohler canister valve rotates after flushing so the chain tightens up and won’t allow the valve to seat. I can rotate it back into position but after 20 or so more a flushes it does it again. Tried different chain adjustments (tighter/looser) but no permanent fix. What can I do now?

 

https://terrylove.com/forums/index....nister-style-toilet-running-after-flush.73056 was an earlier thread. No results from OP on that one.

 

the plastic guide rod may not be working up and down freely. hard water can cause a build up. my toilet was getting harder and harder to flush because it was sticking. the force needed to lift the canister up was increasing because of the sticking. I replaced the gasket on the bottom of the canister and while i had the canister out of the toilet, i noticed the guide rod was sticking. after closer inspection it had a buildup of calcium. i cleaned it and put a little bit of plumbers grease on the rod. there are videos on youtube showing how to remove the canister. after i reinstalled the canister, it flushed like it was brand new, silky smooth

 

I put in one of these toilets in 2012. Worked great for about 7 years. Then the canister would twist as you describe, and the canister wouldn't seal completely. I changed the gasket.. It had a red gasket that had gotten squishy over the years. I think this caused the canister to stick, and when you pulled it up with the chain, the extra resistance caused it to twist in a wonky fashion, thus twisting the chain. I put in a new Kohler yellow gasket, and haven't had any problems since... April 17, 2020.