As of an Android update to 7.1.1 in 6/2018, the newest radio firmware either enables SIM locking to Consumer Cellular SIM cards only, or at least enforces it if previously enabled.
My phone essentially became a brick, as I wasn't able to use it as a phone or an LTE device.
First I tried to just buy an unlock code from eBay. Nobody at the time of this posting was able to generate the unlock code. Consumer Cellular was of NO HELP at all, I'd rather bang my head against a wall than talk to them again.
Luckily for me, BOTH of my parents also had this phone, so I had a few phones to work with and try to get it working.
NOTE: Do NOT just unlock the bootloader and install Lineage, that will not make it work.
It took some doing, but this is how I fixed the issue. It works with a stock phone with a locked bootloader.
1) Download the official image for "harpia" at the link. [mirrors.lolinet.com/firmware/moto/harpia/official/]
2) I used the "Consumer Cellular" version, but I hope that it will work with the others. The "CCAWS" version was the one that I used. (NOTE: If this is not in fact the "Consumer Cellular" version, it did work with my phone version).
3) Copy the following 2 files out of this zip file.
4) Perform the following commands from your command line.
fastboot flash modem NON-HLOS.bin
fastboot erase modemst1
fastboot erase modemst2
fastboot flash fsg fsg.mbn
fastboot erase cache
5) Reboot, and you should have it working now.
6) Turn off all Automatic Updates, you don't want to do this again.
Please let me know if you have any issues and I'll do my best to help you out.