Deb and I took our camper out this weekend on our first trip and discovered our floor was wet at the base of the toilet and soaked into a runner rug. When I pulled it to empty it there was liquid pooling in the recessed areas of the cassette tank on top. Before using our toilet I had removed the cover that goes over the inlet and thought this was simply a splash guard when toting to dump. I was watching a YouTube video on cassette toilets and noticed everyone had the cover installed. I assume this is the reason for the leakage. The flapper O ring is soft and supple and greased with petroleum jelly so I don’t think that’s the problem and the tank is not cracked or damaged.