Joe as far as I know only two of us have had this issue. Although Thetford has told me that they have had issues across several brands I only know of me and Boo that have it going on. I am still working on the issue and I'm concentrating on the touch pad you use to flush. I believe it is a malfunction with that. The plumbing that we can see is all correct and what we can't see it would be difficult to mess up. I have a new pad coming so will see what that does. The toilet is a great toilet and a very expensive one. It has a built in macerator and helps to keep the black tank in good shape. I will figure it out. (Or Boo will and I will copy him).
Phil and Dianna
2011 Berkshire 390 RB