Yorick 323k Damage Dealt?

It took me and my friends quite a while to figure out the problem here. Apparently the damage from Yoricks ult ENDING, is being registered as both true damage dealt AND taken by Yorick (or whoever he ults.) Not a game impacting bug as far as i know, but i thought it was an interesting thing to see. I'm not 100% sure that the ult damage is what causes this, that's just my guess. Let me know what you think.