I was just in a PVP battle and the other side had Staltus on his team. A few of my team died on their turn without attacking. I hadn't attacked yet in the match. All that I can think of is that the passive was triggering but I had not even attacked yet. I think his passive might be triggering when it should not be. There should have been no reason why it triggered. 

The other people on his team were Ronda, Gorgorab, and Arbiter so the damage would have had to have come from Staltus.