The Garmin Messenger does not receive messages through satellite when they are sent as replies to text messages/emails received when a message is sent out through the messenger or messenger app, and these replies are only received when the associated phone is connected to internet. Additionally the MapShare page just gives a generic "Fail" message when attempting to message the device.
Garmin support weren't able to find any issues, can other users verify if their devices receive messages through satellite messages or if the unit is send-only for satellite messages?