Max Transit Mini will not connect after 8.2.1

I have 680 Max transit Mini’s deployed which recently updated to 8.2.1 Firmware. there are approximately 41 of them that will no longer connect to the US Cellular network. can anyone advise if they are having similar issues and if there is a quick fix.

May I know all the Transit Minis are using the same carrier? I suggest opening ticket for us to take a closer look.