Not a Bug, it is intended. When the Revenant diesis killed by Yorick, via 100000True damage.
What am I looking at? Other than Yorick being the damage God that he is?
Yorick in Ascension. I suppose the damage received is from his minions.
The damage dealt must include the ticks that his minions receive passively, and the game code considers Yorick to be causing the damage to them.
It's not a bug; it's a feature.
Last one. http://i.imgur.com/DJMsXpp.png