[PinePhone] SMS validity period not respected

Hello,

I own a PinePhone running postmarketOS. SMS works fine, except that when I send a message to a phone that's offline, it doesn't get delivered when the receiver phone is brought online a few hours later.

I tried sending messages from the command line with nmcli, explicitely setting validity=167 which should give the messages a validity period of 24 hours; unfortunately this validity period is not respected and the messages never reach their destination when I connect the receiver to the network later in the same day. The messages are delivered properly when the receiver is online at the time of sending.

The problem is not specific to postmarketOS, I had the same issue with various other Linux distributions I tried. It also persisted across various upgrades of the modem firmware. Connecting the phone to another mobile network didn't help either, nor did using 3G instead of 4G.

(This issue was also mentioned on the Pine64 forum: https://forum.pine64.org/showthread.php?tid=18203)