When having a weapon/gun in your hand like the UMP, and then switching to any other item (like beans) (but a gun, or maybe any weapon ( big melee, etc.), using the hotbar, it glitches your hands.
They become in this weird state, and can be easily fixed, but looks strange and somewhat an annoyance.
I believe they can be fixed but putting the item away and bringing it back into your hands, or punching with item?