Helldivers 2 is one of the most impressive multiplayer games in recent memory—enjoying such a runaway success that you could barely play it for the first handful of weeks, due to chronically overloaded servers. It's also, unfortunately, a little buggy right now—and I'm not talkin' Terminids.
As highlighted by recent patch notes, damage-over-time effects aren't applied under certain conditions—and certain scopes, like that of the Anti-Materiel Rifle, have been busted for even longer. Sickles can't shoot through foliage...