Damage received tab (while dead) is showing percentage values not adding to 100%

What I have noticed.

Damage percentages don't add to 100%. Damage taken as in health does not add to my full health after engaging at full health and then dying within 5 seconds. I've reloaded the client and reinstalled league and the problem persists. Should I get screenshots or is there a way to view in game current damage using recent games/ spectator mode? Take a look at the screenshot below which shows I was taken from 1603 down to 0 in 6.03 seconds which was actually 100% to 0 so they clipped it some. Also, the minion damage is accentuated twice and is the smallest portion of damage and Kayle did all of the damage but it still doesn't equal that 1603 number. This proves that Riot cannot add to 100. Also, this also implies that damage calculations leading to apparent health loss is not consequential. I believe that there is viable proof that Riot needs to overhaul league damage