I had a service person come out 2-3 weeks ago, but he didn't do anything about my issue.  We had the lens cap fall off of two of the lights within the first couple of months also that I thought he would replace, but  I was told that I had to pay for bulb replacement even though warranty says LED lights are covered under warranty.  He said the flickering might be because the lens came off but it began flickering before that.  So he didn't do anything to our vent hood.