How does something go untouched but just gets buggier as time goes on? (Death Recap)

http://puu.sh/dBLEC/89c266d3e5.jpg

Olaf and Zed both "assisted" killing me and are both taking the same spot in the screen. 937 damage done yet it doesn't show that much. Zed did 140+52 (192) Phys damage and Olaf did 320 true damage. 512 damage shown in the recap. Maybe it was because it was Zac's passive they killed but that's still a bug that has existed for far too long.