I have Lutron "Symphony Series" dimmers in my listening room, and I had the same annoying problem. If your situation is like mine, it's reasonably likely one of your interconnect cables have an anomoly. Ultimately, it came down to a poor connection on one of my balanced connections. I replaced the set, and the problem was resolved. Hopefully you will be able to remedy your situation as easily.
Good Luck.
Good Luck.