Here's something I learned yesterday, tighten the transfer switch contacts. The transfer switch has something like 26 screw in lugs holding the input and output of 3 four-wire sets, and a chassis ground. These lugs get loose after some time. With all power disconnected, shore, genny, and inverter, take a common #2 screwdriver to these lugs and tighten them to 40-ish foot pounds, which is about as tight as one can get. See if this helps. Can't hurt. Then, remove the cover from your 120v CB panel and do likewise in there.