It seems to always happen at the 30 minute mark. Got a longer game where it happened, and damage counts normally after it has gone down, without counting the damage dealt before the 30 minute mark. Im the only person in the match this happens to.
MatchID 35836184
Since the latest updates, damage tracking has been busted. Somehow, at the end of matches, damage dealt to enemy players is dropped SIGNIFICANTLY, something that isnt possible. Also reflected in the scoreboard at the end.
An example is matchID 35758467
30 minute mark: Player damage dealt: 23.278...