Our Fleetwood Prowler 20' TT has been leaking under the bathroom vinyl. I removed the toilet and the vinyl and found that the flange was not screwed down. The toilet was rockable so that explains it. ...
The two bolts that are in the flange's slots are to hold the flange to the floor plywood. If you've had a lot of leaking, the plywood may have deteriorated so that the bolts are no longer holding.