Did 2x LFR's now as BM, didnt get a single Frenzy stack :|
Was your pet actually using its Basic Attack? Some people are reporting that pets are not properly autocasting their Basic Attack.
I noticed this too. I don't think frenzy itself is bugged but the pet's basic attack is, which would cause the frenzy stacks to not go up. I don't know if it actually is bugged or not though.