Since May of 2017, we've deployed around 145 of the Q616. All of them use cellular data, overwhelmingly via ATT and we use skylight to monitor them. They have various feature versions of Windows 10 (1703 - 1803).
Until a couple weeks ago we've had no problem. Then, we had a VZW tablet display the "Device Safety Mode | Temp" status on Skylight (see attachment). In that instance I replaced the SIM and it seemed to work fine after that. We chalked it up to an error with VZW and moved on.
In the past week I've now seen 5 instances of this same problem with ATT Sims. We've made no changes to the OS or software installed. This may not even be a skylight issue at all, but since the cellular experience on these tablets is completely handled by Sierra Wireless, it's the low hanging fruit. When the problem is occurring the network status pop up (from the networking icon in the system tray) displays the cellular status as "cellular 2" (or similar) instead of "AT&T (4G LTE) Connected" (for example).
My solution thus far is to reinstall the WWAN drivers offered on the Q616 Support page. It works, but the solution is mostly temporary. Sometimes multiple reboots work at keeping it running for a while.
We used Dell Latitude netbooks with SIMS for 7 years and never had a problem like this.
This is a very disruptive problem which could end up being very costly above and beyond the time spent fixing it. All of our users are remote and some don't have consistent access to reliable wifi further compounding the issue.
Has anyone seen this? What causes it? What is the solution?