I think I’ve seen this before with Gargos’ minions:
I’m guessing that three things all happened at once, or very close to each other:
- Arbiter’s break #3 (which uses MP+MK)
- The grenade exploding
- Omen’s late attempt to counter-break (which uses MP+MK)
The grenade exploding makes the game recognize Arbiter’s last MP+MK as a counter-breaker, and Omen’s late MP+MK as a break attempt. If I had pressed any P+K combination in my video against Gargos, the same thing would have happened, but instead I was holding up.