we had problems in mirrors with bugged or "dead" mirrors. - a refresh of the beam fixed this
we ran into trouble in the bone guardian room with the stuck skeleton i described. cycling skeleton spawns eventually fixed this
the end boss vanished on us in this run, and was respawned by a gm (which made it invulnerable to shard ritual that is supposed to prevent it from rising again...)
the end boss also bugs out in one of the corners (i forget which, will try and confirm)as happened to Aliclan and us during a run on Llama.