I've figured out why that bug is happening, actually. It's tied to Yorick's ult. If he revives someone, they have a maximum amount of time left to live, though often they're simply killed a second time. But if that timer runs out, the person is dealt 100k true damage (probably pure damage, actually) to very effectively take them down.
Noticed it while playing Yorick in Ascension last weekend. Every time I wasn't killed after reviving myself, a white "100000" would appear over my head as I died. Apparently that damage is being improperly attributed to Yorick.
its a glitch with match history/post game stats, there's been several threads about it
Also, we can't see your match history except for ranked games if we're not friends. Try a screenshot.
I was in that game, it was crazy, i was ezreal 49k damage. Ascension must be bugged at the moment, i really hope riot fixes it and opens ascension again :D Look at enemy Yorick's 11/13/26 with 332.9k damage to enemy champs, and amumu's 137.3k damage to enemy champs. -tajie
link to the match history: http://matchhistory.na.leagueoflegends.com/en/#match-details/NA1/2153420431/37349860?tab=stats