Bug With Breaker's Frenzy?

Is there a bug with the wpvp buff (Breaker’s Frenzy) you get with the Hellbloom PvP gear? It’s suppose to give 2% versatility and 2% movement speed (stacking 10 times) with PvP kills. But my buff keeps falling off for no apparent reason. It’s like one second I’ll get it, then only about a minute later it’s gone. I’m not porting out of the zone or even traveling to another zone. It happens even when I’m staying in the area.