[Bug] Cannot collect chests in mission if you are invited to co-op game while on a map

Like it says, second time this has happened so I was unable to collect any chests on the map after defeating their guardians. While ingame if you are invited to join in a coop match and decline, you are no longer able to collect any chests left on the map. I have not tried letting the invite time out naturally (next step if it happens again).