Quota and maildir does not work with subfolders of INBOX

[Niels Kobschätzki]

Hi,

we just upgraded on FreeBSD (11.2-p14) from Dovecot 2.2 to Dovecot
2.3.7.2 and now we have kind of a big problem: the quota-plugin does not
work correctly anymore. If a user has a subfolder of the INBOX (like
.INBOX.foobar) the quota-calculation does not work anymore. It seems to
be arbitrary but users get counted like double and more than they
actually have in mails (the number of mails is correct, but the size
gets calculated wrongly).
The moment I remove those folders, the size gets calculated correctly.
Unfortunately those folders are generated by some clients automatically
afaik (like .INBOX.Trash)

What can we do about that?

There were already messages to the list about this in July 2018 but I
didn't find any solution
https://dovecot.org/pipermail/dovecot/2018-July/112439.html
https://dovecot.org/pipermail/dovecot/2018-July/112440.html

Niels