I know about leaks causing you issues...drives me crazy too once I get a dry bilge. I had 2 such instances with my 90 P31-2. 1st turned out to be a hole in the exhaust hose right back at the transom...took 2 years to figure that one out

Next was my water heater is right beside the area you mention, and the release valve had weakened and kept letting water out once hot, and it took a bit to figure that one out too, until I actually had a minor flood while on the hard

Hope some of this helps and good luck!!!