Damage mitigated bug

I was playing a quick play open queue match in the map “Colosseo” and i encountered a bug by the mitigated damage section. It says I mitigated 5,000,964 damage in one match.
I don’t know what caused the bug. The heroes i played in the match were Ana and Doomfist, I played as Ana for 89% of the game.
I took a screenshot of the amount of damage to proof it.

Here’s what happened. You nano’d a D.va who then used her self-destruct. Before the bomb went off, the baby D.va died, and the game internally dealt 9,999,999 damage to the D.va bomb in order to “kill” it. Ana’s nano boost gives 50% damage resistance, so you got 4,999,999.5 damage mitigated from the game “killing” the bomb. The D.va just took a bit of damage before using self destruct which contributed to the little bit extra.