I was about 25 hours into darksiders when this glitch happened. *SPOILER ALERT*
I am on the BLACK THRONE level, right after you get to release the 3rd beam. On my way back to AZRAEL I was aproching the door that had the red eye/door that you needed to put the key int to open it and noticed that I never used the key when I came through the first time.
So here i was on the other side of the door, and i still have the door key that i was supposed to have used when i came through the first time.
Needles to say that i cannot backtrack to when i first came upon this red eye/door that , i have already saved my game multiple times over the same save.
So it looks like im gonna be waiting for DARKSIDERS to release a patch for these glithes, because there is no way that im starting over this game from scratch...