Just did a heroic SFK with some friends all using the latest pre mades. I was on my troll feral druid in the pre made gear with full gems and enchants. My health was around 95k and almost every time the boss cast asphyxiation I would take an extra tick when I got down to 1 health, killing me. I was the only person in the party to die from this and it happened about 5 times in a row. Finally I swapped out one of my trinkets for the pre made feral tanking one and it didn't happen.
The weird thing is that before putting on the trinket I survived the odd asphyxiation but would always die on one of the first couple.