Guild Wars 2

So I was fighting fireflys east of Caer Brier waypoint in Sparkfly Fen on my thief and was picking up vigor and fury on random occasions.Im not using vigorous recovery or bountiful theft. And it seems to trigger more when i was fighting multiple opponents. i cant figure out why or where its coming from. I’m just curious if this has happened to anyone?
My build is 0,25,30,0,15
practiced tolerance, Critical Haste,
shadow protector, shadow’s embrace, shadow rejuvenation,
Throw feathers,
full zerker with scholar runes
D/D sigil of force and accuracy

I can say with certainty that Throw Feathers is the culprit here. It’s bugged and it seems that it’s under most peoples radar.

Ahh Thank you,
I was thinking it might of been the one causing it. Dang thats to bad now I’m going to have to give it up, for the fact that i fell like it’s cheating.