Breath of Lightning

[AA0]

even dispell rarely dispells things, you need to know they have just used something to dispell it, mobs have more passive buffs than players.

[Fireclaw]

My understanding was that it dispels as if cast by a level 50 caster. Since a level 50 caster has little chance of dispelling buffs on a much higher level monsters, that's probably why it never dispels.