If you mean the toothed idlers on the RD, that's a chainline issue, and not easily solved. Sometimes tweaking the cage slightly helps, but I don't suggest you try unless you're very comfortable with your skills.

If you mean the smaller rear sprockets, where the chain does abortive shifts to the next larger one, that's usually a trim issue. Try adjusting the RD trim outboard a hair (1/8 turn in on the barrel) and try to find the sweet spot with food shifting both up and down without that problem. If you can't dial it in, it's very possible that the hanger isn't aligned perfectly, which is easy to correct but you'll need a $40 tool.