I'm playing 0.53a on a full install. Though, I did install it over BGT because I didn't want to go through the hassle of reinstalling.... yeah, yeah I know I should've used a fresh install but everything seems to work fine except the 2 bugs I'm reporting here. Feel free to disregard them due to my install.
1. In the sunken citadel I got the key from the kobold priestess that unlocks a door on the same level. There are only empty rooms there and a hidden door that I cannot unlock. In this thread I read something about an undead priest that should be there. Well, he didn 't spawn for me, and I couldn't get past the hidden door.
2. In the basement of the mayor's house in Saltmarsh I can unlock the door with the key from the mayor and I end up in a bedroom with a hidden door. The door can't be unlocked. There is a trap there which gives a message about a hidden switch and a second message after disarming it about the grinding of gears (or something like that). The door still cannot be unlocked.