Melee attack while reloading and attempting to shoot breaks reload, I'm not talking about how a melee strike should interrupt / cancel the reload in progress.
This results the weapon with what ever amount of ammo left can't fire and hitting the reload button will not trigger a reload rendering it useless.
Under the same circumstance a weapon can also glitch out, indicate it has fully reloaded but isn't consuming any ammo when fired and stops dealing damage despite impact animation playing.
If the weapons stops functioning and doesn't want to reload it can be fixed by executing a melee strike first, typically reload will function after this.
When the weapon is stuck at full ammo and isn't dealing any damage, then there is no known workaround that I'm aware off that resolves this issue in game ending match and rejoining the session.