Encountered a bug in co-op where the weapon would only use heavy attack moveset. Would occur when exiting menus, taking damage from enemy, swimming or changing to a different weapon. Occured multiple times with gauntlets and single hand clubs. The opposite would also occur where it would only be light attack with no heavy (not as common). Remedy would be log off and login but would reoccur when one of the following would happen.
Attempted to recreate and it appears the issue stems from sprint on toggle being bound. When toggle sprint is bound and regardless if your standing still or moving the moves set is only the running move set. E.G. The only attack on shellguard gauntlets is a kicking motion. Different from what was initially reported but still a bug.