lost connection while sending end of data error

[Christos Chatzaras]

I use dovecot-lmtp and postfix. When I send e-mail to 2 recipients (or more) at the same time and if one of them is over quota (or under quota and the message I send is bigger than his free space) mailq shows:

-Queue ID-  --Size-- ----Arrival Time---- -Sender/Recipient-------
20B03336F22    26099 Thu Apr 19 18:02:47  support at example.com
(lost connection with server25.example.org[private/dovecot-lmtp] while sending end of data -- message may be sent more than once)
                                        user1 at example.com
                                        user2 at example.com

E-mails sent from the same domain on same server so it's a local delivery.

If I send the e-mail to the over quota user ( only him on To: ) then I get a bounce that says that user is over quota which is the correct behaviour.

I think the problem started after I upgrade dovecot-2.2.35 to dovecot-2.3.1.

Is this a known bug?