6/18 21:37:40.718 Essence of Anger gains Seethe.
6/18 21:37:41.606 Scorpid is afflicted by Seethe.
6/18 21:37:41.617 Vampiric Touch fades from Essence of Anger.
6/18 21:37:41.617 Misery fades from Essence of Anger.
6/18 21:37:41.617 Essence of Anger is afflicted by Unstable Affliction.
6/18 21:37:41.617 Orcmaster gains Shield Block.
6/18 21:37:41.617 Orcmaster gains Reinforced Shield.
6/18 21:37:41.617 Orcmaster is afflicted by Seethe.
6/18 21:37:41.617 Ashlane is afflicted by Seethe.
6/18 21:37:41.627 Schtonkk is afflicted by Seethe.
6/18 21:37:41.627 Pauldin is afflicted by Seethe.
6/18 21:37:41.627 Soulhalo is afflicted by Seethe.
6/18 21:37:41.645 Milohaze is afflicted by Seethe.
6/18 21:37:41.645 Prodomo is afflicted by Seethe.
6/18 21:37:41.645 Gorrilas is afflicted by Seethe.
6/18 21:37:41.658 Nione is afflicted by Seethe.
6/18 21:37:41.658 Benita is afflicted by Seethe.
6/18 21:37:41.658 Asher is afflicted by Seethe.
6/18 21:37:41.671 Kinray is afflicted by Seethe.
6/18 21:37:41.671 Icewolf is afflicted by Seethe.
6/18 21:37:41.671 Epitaph is afflicted by Seethe.
6/18 21:37:50.445 Seethe fades from Essence of Anger.
After that it faded from everyone. I'm not really sure how it works. Our MT was Orcmaster, so he was affected by it for sure, generating more threat. The others are random guys, rogues, mages, resto shamis, hunters, holy priest. Probably just stood in the wrong spot. My combatlot does not show seethe happening in the kill about 1 hour later.
Don't ask me why it didn't come up or how it exactly works, just giving some info here.

That kill was last monday btw, pre patch.