EDIT: OK. This is how it got started. First, when I killed enemies, It was charging it finely. Then a guy joined my game and started to fire enemies. Suddenly I noticed that when they are killing enemies and I am doing nothing, my charger is charging my weapon(The first problem is here: Why should the other guy charge my weapon by killing enemies?). Then they left my game and never came back. Again I noticed that IT IS STILL CHARGING IT WHEN I’M DOING NOTHING.
I’ve double-checked this and I can’t reproduce it. Other player’s kills do not charge your accumulator. Your accumulator slowly charges over time – could this be what you observed?
If anyone else notices this during multiplayer games, please report it.
If so, then I think it was time that was charging weapon, But it was fast like when you kill enemies, It might be the corns that I shot a few secs before (They might get connected to the boss)