[Dovecot] Dovecot IMAP/POP3 auto creating maildir

Hi

I have observed that after deleting a mailbox and removing the user from the userdb, immediately accessing the mail account via POP3/IMAP causes Dovecot to auto create an empty mailbox, because the userdb/passdb details are still cached for 10minutes. Is there any option to tell Dovecot POP3/IMAP not to auto create the mailbox if it does not exist? Alternatively and less desirably is there a mechanism for telling Dovecot to expire a userdb/passdb cached entry?

Running Dovecot 2.1.9

Dominic