Getting regularly mailbox desyncs while syncing with imapc

[Michael]

Hello list!

I sync approximately ~1000 Mailboxes actually without any problems, 
except my very own mailbox - Dovecot 2.2.18 (mdbox format) running here.
The server from where I sync my mails from runs Dovecot 1.2.4 (with mbox 
format).



The last log line that I receive is:

dsync(ms at ddnetservice.de): Warning: Mailbox changes caused a desync. You 
may want to run dsync again.

dovecot error log:

2015-06-30 13:09:50 imap(ms at ddnetservice.de): Error: Corrupted 
transaction log file 
/var/vmail/ddnetservice.de/ms/mdbox/mailboxes/INBOX/dbox-Mails/dovecot.index.log 
seq 2: indexid changed 1435401731 -> 1435662589 (sync_offset=0)



This is the command for running my syncs:

doveadm -o imapc_user=<remote_user> -o imapc_password=<remote_pw> -o 
imapc_host=<remote_host> -o imapc_features="rfc822.size fetch-headers" 
-o mail_prefetch_count=20 -v -D sync -R -u<local_user> imapc: &> 
$LOGS/$BOX.log


A re-run of this command for my mailbox doesn't fix the problem. The 
"Inbox" remains empty.

Only a "doveadm force-resync -ums at ddnetservice.de" fixes this problem 
with the exception that the Inbox still remains empty.
So after force-resyncing I need to run the sync again and my Inbox 
remains consistent until the next imapc sync run.



Actually the desync message is self-explanatory, but I wonder why this 
behaviour only occurs for my own Inbox (only Inbox, other directories 
aren't affected) and not anywhere else.
Is there any possiblity to debug this? Could also the amount of new 
incoming mails cause this or do I have maybe a bugged mail in my 
original mailbox that is causing my trouble?

Any hint is appreciated.
Thanks,

Michael