SMS list different between mmcli and AT commands

[Matthew Via]

On my pinephone pro I occasionally miss an SMS.  I'm not sure which circumstances lead to the missing messages, but if I use AT commands to query the modem, I have an (over time, growing) list of messages that don't get deleted.  Some of these are badly handled multipart messages, but some are just simple text messages that are still marked UNREAD, and never made their way into chatty somehow.  In all of these cases though, the mmcli output is empty:

# mmcli -m 0 --messaging-list-sms
No sms messages were found

However:
echo 'AT+CMGF=1' | sudo ./atinout - /dev/ttyUSB2 -

OK
echo 'AT+CMGL="ALL"' | sudo ./atinout - /dev/ttyUSB2 -

+CMGL: 0,"REC READ","xxxxxxxxxx","22/04/02,09:48:09+00",,129,3
...
+CMGL: 1,"REC READ","XXXXXXXX","22/06/22,22:18:38+00",,129,6
...
+CMGL: 2,"REC READ","XXXXXX","22/06/22,23:25:26+00",,129,7
...!
+CMGL: 3,"REC READ","XXXXX","22/06/22,23:31:23+00",,129,5
...
+CMGL: 4,"REC READ","XXXXX","22/06/23,12:01:16+00",,129,4
...
+CMGL: 5,"REC READ","XXXX","22/06/23,18:50:55+00",,129,84
...
+CMGL: 6,"REC READ","XXXX","22/06/23,19:07:24+00",,129,48
...
+CMGL: 7,"REC READ","XXXX","22/06/23,22:00:20+00",,129,132
...
+CMGL: 8,"REC READ","XXXX","22/06/23,22:00:20+00",,129,132
...
+CMGL: 10,"REC READ","XXXXX","22/06/24,13:30:49+00",,129,3
...
+CMGL: 11,"REC READ","XXXXX","22/06/24,13:30:58+00",,129,23
...
+CMGL: 12,"REC READ","XXXX","22/06/24,16:35:40+00",,129,34
...
+CMGL: 13,"REC READ","XXXX","22/06/24,16:35:56+00",,129,22
...
+CMGL: 14,"REC READ","XXXX","22/06/24,16:36:06+00",,129,16
...
[ more truncated ]
+CMGL: 48,"REC UNREAD","XXXX","22/07/11,22:20:25+00",,129,30
...
+CMGL: 50,"REC UNREAD","XXXX","22/07/16,22:03:11+00",,129,56
....
+CMGL: 51,"REC UNREAD","XXXX","22/07/17,18:10:56+00",,129,134
...
+CMGL: 53,"REC UNREAD","XXXX","22/07/19,18:03:05+00",,129,48
...
+CMGL: 54,"REC UNREAD","XXXX","22/07/19,20:36:16+00",,129,1
...
+CMGL: 55,"REC UNREAD","XXXXX","22/07/19,20:36:23+00",,129,12
...
+CMGL: 56,"REC UNREAD","XXXXX","22/07/19,20:36:28+00",,129,16
...
+CMGL: 57,"REC UNREAD","XXXXX","22/07/19,20:36:34+00",,129,17
...
+CMGL: 58,"REC UNREAD","XXXXX","22/07/19,20:49:02+00",,129,22
...
+CMGL: 59,"REC UNREAD","XXXXX","22/07/19,20:49:14+00",,129,27
...


The "REC READ" messages accumulating is an issue since when it fills up (100), all inbound SMS's get dropped, so I need to regularly (every week or so) use AT commands to purge them.  The "REC UNREAD" ones I just never receive unless I regularly query the modem as above.  However, unless I am misunderstanding the mmcli command, the main issue here seems to be that modemmanager is unaware of the messages in the first place.  What next steps are there to debugging these issues?

This is a Pinephone Pro running Mobian using the open source modem firmware (0.6.7), though I had the exact same issue on my non-Pro pinephone running PostmarketOS.  Currently this is MM 1.18.10, though I've seen the issue since I started using the phones, and that was on 1.18.2.

Thank you, Matthew