Recently, on Maguuma server at least, Claw has been spawning untargetable Corrupted Ice Shields. The wall will break for the first time, then never respawn graphically and be unselectable by normal methods. Apparently if you turn on auto targetting and attack, you will get the target, but otherwise you must AoE it instead to hit it. If you AoE it, it does take damage, but for me (Necromancer, staff) at least it would not take damage with normal attack. This glitch was experienced by everyone at the event, and we submitted bug reports for it as well.
The quest seems to function normally, but the wall itself is glitched.