dovecot flags lost after move/copy

[ciuga]

Dear Community,

I have a issue with our dovecot server ( 2.3.4.1 (f79e8e7e4) ) with
maildir

Flags are lost after a copy (or move), as you can see on this exemple
: 


* Before doing anything, list detail of a mail :
doveadm fetch -u XXX flags mailbox-guid
f303160f6df58c5b67040200bc34b0e6 uid 46126
flags: \Seen $Labelimportant

File name also contents the 'e' at the end :

1628631415.M671664P17659.mail7,S=14835,W=15111:2,Se

* Copy it for testing

doveadm copy -u XXX Archive mailbox INBOX mailbox-guid
f303160f6df58c5b67040200bc34b0e6 uid 46126

* Fetch flag of this new mail 

doveadm -v fetch  -u XXX flags mailbox Archive
flags: \Seen

File name also don't content the flags
-rw------- 2 XXX users  14835 août  10 23:36
'1628631415.M671664P17659.mail7,S=14835,W=15111:2,S'

Do you known how to keep flags after move and/or copy ?

Thanks in advance
-- 
Chris