I just finished a ride in which my chain was busy chatting with the 50T cog and the derailleur or chain or cassette decided to play switch and slip when I used 34T and the 3rd highest gear

I've measured the chain and it's not stretched out. I had the front derailleur adjusted because I was losing the chain between the 50 and 34 cog, whether I was shifting up or down. Now the rear is jumping from the 2nd and 3rd highest gear even though I've adjusted the rear derailleur. The teeth on the cassette do not look worn and I don't see any light between the chain and the cassette.

I have a SRAM OG 1070 11-28 cassette. Is this the nature of the beast? Do I need to replace anything? I have had this bike for a year now and put about 4000 miles on it. Thanks in advance.