NOTIFY regression: 2.18 no longer notifies of events in INBOX

Here is an example with APPEND

$ /usr/lib/dovecot/imap
S1: * PREAUTH [CAPABILITY IMAP4rev1 … MOVE NOTIFY SPECIAL-USE] Logged in as guilhem
C1: a1 NOTIFY SET (INBOXES (MessageNew MessageExpunge FlagChange))
S1: a1 OK NOTIFY completed (0.000 secs)

$ /usr/lib/dovecot/imap
S2: * PREAUTH [CAPABILITY IMAP4rev1 … MOVE NOTIFY SPECIAL-USE] Logged in as guilhem
C2: a2 APPEND INBOX {1+}
C2: x
S2: a2 OK [APPENDUID 1384472528 26085] Append completed (0.229 secs).

With 2.13 from Debian Jessie, S1 sends a notification for the new message in INBOX, as expected:

S1: * STATUS INBOX (MESSAGES 4333 UIDNEXT 26086 UNSEEN 1)

However it doesn't with 2.18 from Debian Sid, as if ‘INBOX’ was excluded from the mailbox filter ‘INBOXES’. It does send a notification for ‘virtual/unseen’ instead (as expected), but nothing for ‘INBOX’.

S1: * STATUS virtual/unseen (MESSAGES 3 UIDNEXT 15186 UNSEEN 3)

This is INBOX-specific because APPENDING the message to another mailbox triggers the notification on both 2.13 and 2.18 as expected:

S1: * STATUS test (MESSAGES 2 UIDNEXT 3 UNSEEN 2)
S1: * STATUS virtual/unseen (MESSAGES 2 UIDNEXT 15195 UNSEEN 2)

I attach the ‘dovecot -n’ output for both 2.13 and 2.18.

-- Guilhem.