When sending SMS from Inreach, sender ID on GSM phone is shown as "MSGREP" instead in satellite phone number form

In the last two weeks (I think after March, 25th) the sender ID of the SMS sent from Explorer+ to my GSM phone sometimes was shown as "MSGREP" instead in satellite phone number form like +1 (201) 1234-5678. In thi case, it was not possible to reply to Inreach sender with SMS, as using MSGREP instead SMS address does not work. Last days it seems the system is providing InReach sender phone number in proper form again.

Any idea why or when is this happening? Replying to received SMS is one of the essential elements of InReachsystem (I believe).

Remarks: sometimes at the time when I was sending message from InReach (beep signal) the receiving GSM phone was not available (not more than 30 minutes). The message was received after 4 hours or so, usually it comes in two or three minutes after the InReach beep. The phone receiving the message is registered as "contact" mobile phone in the Inreach Explore account tab, phone number was properly addressed in all cases.

Thank you!