The ghost of a chance end puzzle currently has a puzzle piece that will not light up when given power from the left side. The specific puzzle piece is not broken however, as it still lights up and passes power on from right to left as well as being able to activate the trap above the tile. As far as I can tell, it occurs ever time on Heroic Elite (I have run 11 times trying to see if I could complete the puzzle with no success).
I had the same trouble on this corner 8 months ago, I bug reported it and filed a ticket to a gm for the quest completion but it seems that it hasn't been fixed yet.
Here's a video for demonstration of the bug