I think there's an issue with Population Bomb. For some reason in this battle, it only hit 3 times on this turn.
https://replay.pokemonshowdown.com/gen9nationaldexbh-1912978373-34xgmvf3pjs6icesafh9v4vf6uvw8dnpw
Now, at first I thought I missed the 4th hit, but it doesn't say that at all. And...