Sorry if someone mentioned this already, but I couldn't get Debuff type increased magic damage to work. When someone had Curse of the Elements up (cast by me or someone else), it never recognized it.
How did you attempt to setup this aura? I just made one that recognizes CoE and Master Poisoner by setting those two different matches to the main trigger, and it works fine. What did you do specifically? It sounds like you may have tried to make an aura for the debuff type rather than making multiple spell matches. As far as I know, that doesn't work.