Bug with counter attack

So I was in arena my opponent use tommus legendary weapon and proc so I have 3 target being hit. My tommus and saarvin. I had my counterattack activated with saarvin and tommus legendary gauntlet proc so he counterattack but my saarvin did nothing even if he was hit.

I’ve had this issue as well, though I can’t remember the exact circumstances. Saarvin and Tommus both had counter attacks in effect when they were both hit by something, and only Tommus attacked.