smsd reading SMS leaves Nokia 3109 classic in inconsistent state

[Hartmut Benz]

Hi folks,
I am using smsd postgresql with a Nokia 3109 classic.
Incoming SMSs are read and transferred to the database correctly, but
the phone does not recognize/see that the SMSs have been removed. The
phone continues to indicate 'n unread messages' (or some such), and when
I try to read them directly or navigate to the Inbox (on the phone), an
error message appears that 'the operation failed, please try again'.
Repetition does not solve the issue, only switching the phone off and on
does.
I do not know how serious the situation in the phone is, for instance if
more catastrophic failures would appear after a few dozen or hundred SMS
have been processed.

This behavior started with 0.6.27 and is also found in (my) latest
git-version from about 4 or 5 days ago.
In version 0.6.26 that I have been (and now again are) using, SMSs are
correctly removed from the phone. When an SMS arrives, the phone's
display shows '(n) unread messages'. When smsd subsequently copies and
deletes the SMSs on the phone, the message indication vanishes, and at
any moment I can navigate into the phone's Inbox without any error message.

Any suggestion what is going on here?

/Hartmut