ATT Surface 3 can stay aside of this issue, since it uses its own set of drivers, different than for "Norht America, outside of US".
In one of history update description on Microsoft site i read:
In January 19 Release:
In addition to the updates list above, the following additional update is available for Surface 3 (Verizon 4G LTE):
- Surface IA7260 Firmware Update (v1544.01.00.28) improves mobile broadband network stability.
Might be this fix is similar to my issue
So I have an UNLOCKED LTE for the US. I'm using it on Verizon VZW has not been offered to me. The update you refer to is specific to the dedicated VZW SKU. I have no idea of how these vendor specific updates work, but will ask.