After I emptied the tanks, it stopped. On the downside, today, the black tank is making the kitchen smell like a urinal. Nothing like fermented urine to make your day. Stinks so bad that people were literally walking away from the camper when we were stopped for fuel or food on the trip back. I have the exhaust fans blowing full blast. I think it's time to call a service tech.
edit: after a bit of Google searching, it could be the AAV. Going out there tomorrow to check it out.
#2 Couldn't stand it and went out to check. Definitely the AAV. Ordered another one. I'm figuring out this camper little by little, but I think I'm also going to go ahead and take the RVTI courses to get certified. There are no certified mobile techs in our area, and it would be a good opportunity to do some education and provide a living for my sons, who are very interested in working on the camper with me. The good thing is that one of them is in training to get Cummins certified as well.