Missing mailboxes after migration from Maildir -> mdbox

[Ansgar]

I migrated from existing dovecot Maildir to dbox.
After adding separator to the namespace it migrated all Inbox mails, but 
the other mailboxes like user-created ones and "Junk", "Sent" and so on 
has not been migrated.

Any advice would be helpful, here is my dovconf:
https://pastebin.com/rDSeBcLe

My migration I made using: 1. Edit dovecot.conf with new mdbox and 
adding separator 2. dsync mirror per user with old maildir:~/mail 3. 
missing mailboxes: tried with doveadm sync also with -f mode and 
specified mailboxes. No luck.

dsync -v -u admin at sajdowski.de mirror maildir:~/mail
mail_home = /var/vmail/mailboxes/%d/%n
#mail_location = maildir:~/mail:LAYOUT=fs
mail_location=mdbox:~/mdbox

My directorys:

root at mail:/var/vmail/mailboxes/example.de/admin# ls -l
insgesamt 56
drwxrwx---  2 vmail vmail 4096  8. Mär 01:14 cur
-rw-rw----  1 vmail vmail  160  8. Mär 01:14 dovecot.index.log
-rw-rw----  1 vmail vmail 3712  8. Mär 01:14 dovecot.list.index.log
-rw-rw----  1 vmail vmail   96  8. Mär 01:14 dovecot.mailbox.log
-rw-rw----  1 vmail vmail   51  8. Mär 01:14 dovecot-uidlist
-rw-rw----  1 vmail vmail    8  8. Mär 01:14 dovecot-uidvalidity
-r--r--r--  1 vmail vmail    0  8. Mär 00:57 
dovecot-uidvalidity.6407cf6d
drwxrwx--- 20 vmail vmail 4096  8. Mär 02:51 mail
drwx------  7 vmail vmail 4096  8. Mär 13:52 mailboxes
drwx------ 13 vmail vmail 4096  8. Mär 02:36 Maildir
drwx------  5 vmail vmail 4096  8. Mär 04:20 mdbox
drwxrwx---  2 vmail vmail 4096  8. Mär 01:14 new
-rw-rw----  1 vmail vmail   28  8. Mär 01:14 subscriptions
drwxrwx---  2 vmail vmail 4096  8. Mär 01:14 tmp
drwxrwx---  2 vmail vmail 4096  8. Mär 00:57 xapian-indexes

root at mail:/var/vmail/mailboxes/example.de/admin/mail# ls -l
insgesamt 87576
drwxrwx---  2 vmail vmail  9113600  8. Mär 02:20  cur
-rw-rw----  1 vmail vmail  1602296  8. Mär 02:20  dovecot.index
-rw-rw----  1 vmail vmail 73030876  8. Mär 02:41  dovecot.index.cache
-rw-rw----  1 vmail vmail   441656  8. Mär 02:39  dovecot.index.log
-rw-rw----  1 vmail vmail    83568  8. Mär 02:20  dovecot.index.log.2
-rwxrwx---  1 vmail vmail   206490 17. Jun 2019   dovecot.index.thread
-rwxrwx---  1 vmail vmail       51  2. Aug 2019   dovecot-keywords
-rw-rw----  1 vmail vmail     1392  8. Mär 01:25  dovecot.list.index
-rw-rw----  1 vmail vmail     6712  8. Mär 02:41  dovecot.list.index.log
-rwxrwx---  1 vmail vmail     1464  8. Mär 02:20  dovecot.mailbox.log
-rw-rw----  1 vmail vmail  4875528  8. Mär 02:20  dovecot-uidlist
-rwxrwx---  1 vmail vmail        8  8. Mär 01:25  dovecot-uidvalidity
-rwxrwx---  1 vmail vmail        0 17. Jun 2019   
dovecot-uidvalidity.5a6912f0
drwxrwx---  5 vmail vmail     4096  7. Mär 20:14  Drafts
-rw-rw----  1 vmail vmail       49  6. Mär 11:10  maildirsize
drwxrwx---  5 vmail vmail     4096  7. Mär 20:44 'Mailling Listen'
drwxrwx---  2 vmail vmail   204800  8. Mär 00:04  new
drwxrwx---  5 vmail vmail     4096  7. Mär 20:14  Sent
drwxrwx---  5 vmail vmail     4096  7. Mär 20:44  Spam
drwxrwx---  5 vmail vmail     4096 26. Feb 19:44 'SPF Fail'
-rw-rw----  1 vmail vmail       23  8. Mär 02:20  subscriptions
drwxrwx---  2 vmail vmail     4096  8. Mär 02:20  tmp
drwxrwx---  5 vmail vmail     4096 26. Feb 19:12  Trash
drwxrwx---  5 vmail vmail     4096  7. Mär 22:30  ubb
drwxrwx--- 10 vmail vmail     4096 27. Feb 18:44  xapian-indexes