Watch closely at the 'Hex of Vengeful Corruption' Timer, how it went from 13 seconds left, to 0 Seconds Left.
This has happened during my third attempt of Solo Flawlessing the Warlords Ruin Dungeon. I died afterwards because of other enemies, but if this didn't happen I wouldn't have been thrown off course.
I'm not attempting this dungeon solo flawless again until this bug is fixed, as I won't be able to reliable tell when the killing debuff is nearing the end. That Timer is critical for any Solo Flawless attempt, so this needs to be looked into and fixed