Combustion isn’t working in the Cataclysm Pre-Patch, I press it and nothing happens and after 2 seconds it says “You can’t do that yet.” but I assume that’s because no DoTs are on the target anymore.
It’s like it wants to cast it, I do hear a fire effect of some kind when pressing it but no animation happens and the spell doesn’t go off.
Edit: I should specify where I was, I was in Ironforge hitting dummies.