#1 - Sept. 23, 2011, 9:41 p.m.
http://tobias.kemonoart.org/Temp/Screenshot001.jpg
http://tobias.kemonoart.org/Temp/Screenshot002.jpg
http://tobias.kemonoart.org/Temp/Screenshot003.jpg
Above you find a dead end with an unpolished edge to it. And then by the mouse cursor, you'll see the stairs are misaligned with the previous block.
Also, while they are not bugs, two other odd things happened for me in this instance of the dungeon. The Resplendent chest dropped a single white item and gold, nothing more. (Edit: This happened on my second time in the dungeon as well. 107% MF and not a single item of value.) This is with 94% MF at the time, so it seems really abnormal. Perhaps some items got lost behind the wall or something.
The other weird thing was that during this Den run, I obtained an amulet. I had yet to see amulets prior to this. There aren't even any on the AH. Abnormal, but not likely a bug. (13% MF amulet, woot!) I believe I obtained it from the Plague Carrier bats on level 2.
Edited to add more screenshots.