Corrupted index cache after migrating from maildir to mdbox

[Tim]

Hi guys,

I'm running dovecot/postfix on my Debian Jessie maschine:

# dovecot --version
2.2.13
doveconf -n output: http://p.bastelfreak.de/HsVwS/

today I migrated from maildir(located at /var/vmail) to mdbox with these
commands:
rsync -av -f"+ */" -f"- *" /var/vmail/ /home/vmail/
rm /home/vmail/*/*/Maildir -rf
for i in $(doveadm user \*); do u=$(echo $i | cut -d@ -f1); d=$(echo $i
|cut -d@ -f2); dsync -v -u $i mirror mdbox:/home/vmail/$d/$u/mdbox; done

Then I changed the mail_location to mdbox:/home/vmail/%d/%n/mdbox and
did the following commands:

service dovecot restart
for i in $(doveadm user \*); do u=$(echo $i | cut -d@ -f1); d=$(echo $i
|cut -d@ -f2); dsync -v -u $i mirror maildir:/var/vmail/$d/$u/Mail; done
doveadm index -A all INBOX
for i in $(doveadm user \*); do doveadm -Dv fts rescan -u $i;done

unfortunately I'm getting the following two kinds of error messages for
all mail boxes in my mail.log:

Error: Corrupted index cache file
/home/vmail/%domain/%user/mdbox/mailboxes/%maildir/dbox-Mails/dovecot.index.cache:
Broken virtual size for mail UID 2564

and:

Error: read(/home/vmail/%domain/%user/mdbox/storage/m.108
): FETCH BODY[] for mailbox %maildir UID 2564 got too little data: 2417
vs 6319

please let me know if you have any suggestions for fixing this issue or
if you need more information.

kind regards, Tim