Device Connector not connecting to UBR without WAN

Our network setup involves the use of Pepwave IP55 Device Connectors that wirelessly connect to a Pepwave UBR LTE. The trouble for us is that this does not happen unless the UBR is connected to WAN. When WAN is connected, the Device Connector will connect to the UBR just fine and it will stay connected even if internet is lost until either device is rebooted.

For our use case, we cannot rely on having a continuous internet connection, but we need the Device Connector to reliably connect to the UBR every time. Is there a way for us to bypass this requirement for internet or spoof a connection to WAN for the UBR?