Since this issue has been around for over a year now, and i’m amazed (not really, my expectations of humanity are quite low) that the dev team doesn’t play GW2 enough to test their own code. I’m not going to specify which skill is causing issues in WvW, because a year+ of the same problem is kind of ridiculous.
It’s a skill of the Guardian’s, and is one of the five skills that the Staff has. Good luck.