Boron thinks it's online, console disagrees

I’ve been testing my Boron LTE based device prototypes for a while and recently observed the following edge case. The main test site is in Dallas, TX has been going for a few months with no issues other than just rare connection drops which are self-healing. Then I took one of the successfully tested devices to Chicago, IL, it worked there for about a day and then disappeared from the console. The device’s LED is breathing cyan and it just sits there thinking it’s connected but there are no events in the console (normally it publishes status every 5 minutes) and the last handshake status shows many hours ago. Obviously, attemps to retrieve any kind of telemetry don’t succeed either. The power reset (disconnect and connect the battery) put it back online, but then it repeated once again. I’m not going to stay here for long, not sure if will be able to reproduce but just want to ask what conditions could put Boron in such controversial state.