I recently turned in a P45+ to Phase One in Denmark after it started to act strangely. Their investigation found signs of water corrosion in the internal circuitry, which they suggest to replace (please spare me any references to the repair cost ).
I do recall the back being exposed to some light drizzling rain and being close to oceanfronts and waterfalls during its lifetime, but the camera certainly didn't get drenched with water on any of these occasions. Also, I never noticed any signs of water inside the back (such as moisture around/on the sensor, or a fogged display). At home, I always store the camera in a dry place with low humidity.
So I wonder if there are any possibilities for weather-sealing the back a bit more in DIY manner for the future. I've been thinking about taping the buttons and the CF card bay prior to shoots where I may encounter wet conditions, but maybe there are more effective options. Any ideas?