Sounds like your bowl fresh water valve may be leaking allowing water to enter the bowl. Ours will leak a little into the bowl if the campground water pressure is on the low side but after a short time it will completely close.
BTW, in you last post, it sounds like you may be leaving you black water tank dump valve open to keep your tank empty. If that is the case, you may end up with the dreaded 'pyramid' in the tank. It's a good idea to keep the tank valve closed until you need to dump...that way there's ample water to rinse out the solids/paper. We try to use extra water when flushing the bowl...well, unless we are dry camping. My apologies if you already knew that little tidbit. Bob