[Dovecot] Panic in index-sync.c: line 25 on dovecot-1.2.17

Hi,

with dovecot-1.2.17 (yes i know it's old) i'm getting the folowing error after doing a system upgrade.

May 7 22:04:26 mail dovecot: deliver(elon): Panic: file index-sync.c: line 25 (index_mailbox_set_recent_uid): assertion failed: (seq_range_exists(&ibox->recent_flags, uid)) May 7 22:04:27 mail kernel: pid 79989 (deliver), uid 4873: exited on signal 6 (core dumped)

this only happens to one user and only with mail from one mailinglist (this one). Mails do get filtered by sieve. After some delivery attempts the mail finaly gets stored alright in the maildir.

May 7 22:23:27 mail dovecot: deliver(elon): sieve: msgid=: stored mail into mailbox 'dovecot' May 7 22:23:27 mail postfix/local[82289]: 7DED511402: to=elon@physik.tu-berlin.de, orig_to=l.messner@physik.tu-berlin.de, relay=local, delay=1141, delays=1141/0.01/0/0.26, dsn=2.0.0, status=sent (delivered to command: /usr/local/libexec/dovecot/deliver) May 7 22:23:27 mail postfix/qmgr[1303]: 7DED511402: removed

After that a new mail does the same dance (perhaps until the next one to this ML arrives). The maildirs are on NFS and in this case only beeing used with my instance of mutt and two other postfix+dovecot servers which are quite idle. Whats the way to debug this ?

Thanks, Leon