And you can replace the same seal in the window and next time it will not leak, indicating no permanent damage. So it is not damaged in the sense that a badly loaded boat has pushed up against it and nicked it so it leaks. In fact I can't see how loading the boat would ever make a difference to the integrity of either of the seals, considering how they are located completely inside grooves. SO you need to go carefully around the DOOR sealing surface and screw thread with say ethanol on a cotton bud once a week. AND the seals on the drain valve on the bottom need regular cleaning for the same reason.
Grit washes down the drain and scores the sealing surface and O rings in the valve.
In fact if you have never done it, go and clean the door seal and drain valve right away. You'll be surprised at the gunge that will be there. My explanation is to do with seal elasticity. When the CPD is cooled before being pressurised, the neoprene seals lose much of their elasticity and do not expand properly to seal when the chamber is pressurised. So the solvent leaks out and as the seal stays cold it will never seal properly as of course you keep the chamber cold to ensure fast fluid transfer.