The embodiments herein relate to a method performed by a gateway. The gateway detects that a procedure for activating or deactivating a bearer has been initiated. The gateway receives a first modify bearer or modify access bearers request message for the same PDN connection and UE as the bearer activation or deactivation procedure is intended for. The gateway detects a bearer mismatch between a first set of bearers and a second set of bearers known by the gateway and associated with said same PDN connection and UE. The gateway accepts, during a time interval, the received modify bearer or modify access bearers request message even though the bearer mismatch has been detected.