Currently there is a energy bug with Ferocious Bite for feral druids which I recently noticed when I took part in a mc run as feral dps.
Bug: No matter how many combo points you have acquired on your target (not implying it should be dependent on combo points just did some testing), Ferocious Bite will empty ALL your energy when used and not 35 energy which the ability states it should ONLY use.
Kevinpeace, Zeth'Kur.