In the 30's range of floors where the octopus mobs are, there is a bug that locks a pile of mobs in the entrance to the area against the cave wall.

They will be on your hate list but if you try to attack them you see the "Protect" animation like it has on protect, every strike but they take no damage and do not attack back.

I even tried to use Limit Break, it didn't work, zero damage.

Of course because these mobs are needed to complete the run enough to use the portal to the next floor it basically locks you from being able to move to the next levels.

We thought we were going to have to just abandon duty but we decided to try killing them while in the Rage beast suit. It killed them. This is the only thing that allowed us to attack the mobs and the only way they could be hit for damage.

The bug happened twice and both times the Rage suit was the only way to kill the mobs. I will report it to bug forums but I wanted people to know heads up.