HIGHESTMODSEQ replication issue

[Gustavo Ajeitos [Office365]]

Hello,

I'm using dovecot 2.3.10 in OpenSUSE and I have configured a 
master/master replication between two backends, it works well but I have 
found an issue with the replication of the HIGHESTMODSEQ.
When I move a set of message from a mailbox to other, e.g. move 3 
messages from INBOX to Junk, the HIGHESTMODSEQ get different on each 
server, with no errors in the log:

[Borrador] 34:34
[Sent] 63:63
[Drafts] 12:12
[Trash] 146:146
[Junk] 219:218
[INBOX] 1133:1130

It can be fixed executing a full sync:
$ sudo doveadm -D -v sync -u user at test.priv -d -l 30 -U

But it is not a solution because it happens all the time that a user 
move messages.

I'm using ActiveSync and the ActiveSync server use the HIGHESTMODSEQ as 
part of the synchronization key (sync_key), so in that situation the 
server detect changes on the mailbox if it connects to the backend with 
a different HIGHESTMODSEQ that it previously cached, causing a loop 
beetween the ActiveSync server and the the email client, where the 
server constantly inform email client about nonexistent changes.

Could it be a bug in Dovecot replication? How can I solve it?

Best regards,
Gustavo Ajeitos