Garmin Messenger app asks for SMS auth when out of cellphone range

Is that just a really bad design or a one time blip?

Was in the moutains and wanted to send my spouse a message via inReach that I would be home much later than expected.  Launched the Android messenger app and it asked me to conform my cell phone # via SMS.  Which is is exactly the wrong time when I am out of cell phone range.  Makes inReach texting kind of pointless.  (Don't know if SOS texting would have required it too ;-)

Are there any best practices to avoid this in the future?  Always send a message before I rely on inReach?