The Doomguard from Warlock's Ritual of Doom has been nerfed in some of the most recent hotfixes on live servers.
These hotfixes now appear to be live.
As mentioned by our Affliction Warlock writer, Kalamazi, in his recent YouTube video, Doomguards were doing an incredible amount of damage — specifically the one from Ritual of Doom. This hotfix seems to curb this interaction, likely meaning Ritual of Doom was never supposed to do this much damage.
You'll notice that a lot (#1, #2, #3, #4) of the top logs for Affliction are using the Doomguard to put out fantastic numbers, but unfortunately no longer.