We have fixed this new Multiplayer Damage issue - please update your game.
Sorry for this mistake, but long-time expected fixes in MP which we're working on requires very deep investigation and changes. Some things can't be located in internal test due to their random or specific nature. Anyway, we have located and fixed this issue as soon as it was possible and there less than 24 hours have pass from 3.009 release till this fix.
IL-2 Sturmovik team.