Death recap bug everyone knows about.

tl;dr Just wondering if anyone actually does have a plausible explanation. I'm certain it's been posted a thousand times before, but I'm just wondering if an explanation has ever surfaced, because I haven't found one. I'm upset because I can't be sure I'm dying when I should.

Everyone knows the death recap is so ridiculously inaccurate that it's absurd it even exists.

The "best" (most popular) explanation I've found is that it doesn't count anything but the last X sources of damage, or sources you've taken in the last X seconds... yada yada. An easy anecdote that simply proves this is not the case, I was playing Urgot in URF a few minutes ago, have 4000hp and a ton of tank, and I die to a Yi+Ori combo in ~2 seconds. Okay, I get it.
I check death recap, and the total damage given to me adds up to ~1800. I wasn't hit by anything else, no minions or turrets to screw it up, just those 2. Yeah, I think I was doomed. No chance of survival. But the damage it shows really begs the question: should I have died quite when I did? When I see a damage report like that, how should I not conclude that I died to a bug? It shows so little damage, and I was so strong. I mean, I was so TANKY. (and strong. If I really took only the damage they showed, I would have 2v1'd them without blinking, with the whole visage+deaths dance, not to mention my W shield, mitigating that damage.)

IS there any explanation for this incredible inaccuracy better than what I said above? Honestly I cannot fathom how this... I mean, it's gotta be a relatively-easy thing to code compared to the rest of League... what's going on?!

(If there is a better forum for this, let me know; but since I know this is a VERY known bug, I wasn't going to post in "bug" section)