Hello Jerome,
The problematic RUT950 routers have the latest firmware loaded. I am seeing connectivity problem.
Scenerio1: Changing the Service mode from say 4G Only to 3G Only, the router will have connectivity issue. It will not be able acquire a new IP address on the new service mode until the router is restored to factory reset.
Scenerio2: When the router locked on a particular service mode and working perfectly losses power or get rebooted, when the router boots up fully again, it is not able to acquire IP address on the same service until once again the router is restored to factory reset.