I recently finished my five-hour long search for the damn level ten secret room. I then proceeded to kill the boss, and got great equipment. After resting, I went back to ten to repeat the process, and I found the secret room in under fifteen minutes. SWEET! I proceeded down once more to level 11. Once I had traveled nearly every square on the dungeon, I was about to find the boss. I had gathered staves, Excaliburs, tomes, and more, when I checked my inventory. At the last encounter, I had found a Patriarchs Gem. The gem and all of my equipped items were in the inventory, along with three or four other TOTALLY RANDOM items, but that was all. I had lost over 50 very rare staves and gems. I had to lose an hour of play time to go back with a temporal save.
Note that when this happened, I was in the dungeon. I had not reached my max carry limit, and I had no dead characters.
Thanks, Paladin