MR1100 DNS forwarding stops until reboot or Band Region Change

I have an MR1100 with an OTRMobile account using AT&T.  I have been having issues for a few weeks were DNS Forwarding stops working.  To resolve this I was rebooting the router, but I also found that changing the Band Region between Auto and LTE All will also fix it.  I have exhausted all options through OTRMobile support with factory resets, 3 new sim cards, I have even tried connection through the Network port and via the onboard wifi, it all works the same.  I even Tried my LB1120 and it did the same thing but didn't have the band region switch option only reboots.  

has anyone seen this before and have any ideas on what I could try next?

Currntly I have to do a band region change about 4-6 times an hour  to maintain connection. 

Thanks in advance!