Our 2005 Bavaria 36 had the boot or diaphragm replaced 2020. This was the year to replace the thruhulls and valves as there was a bit of rust and discolouration possibly from corrosion showing on the holding tank valve.
The removal of the head intake thruhull and valve went fine. The holding tank thruhull was next. When I removed the hose clamps and tried to loosen the hose from the hose barb on the valve, the hose barb broke away from the valve inside the hose. Yikes. You can imagine my surprise. No telling when the hose and hose Barb would of separated from the valve and flooded the boat. While I do close my valves while I am not staying on the boat but not when we row to shore, visiting etc.
The valves and thruhull I used for the head intake, holding tank thruhll and a new wash down pump thruhull were all Trudesign. Installation was simple and secure with the load bearing collars.
Just my experience. Hope you check your thruhulls and valves.