Aftergame "magic damage"
I put this under bug report, because i can not think of how vayne or sivir did magic damage only 2 things i could think of. 1 - Spellblade mastery (but i didnt have it on and neither did vayne) 2 - Ardent Censer (but neither support bought it)
Heres a screenshot of it. vayne did i think 42 magic damage. and i did like 76