IMAP proxy auth - logs in as admin if user is absent
While syncing accounts from an older server to OCUCS with the imapsync script, I found today that when using IMAP proxy auth (with OUCS 7u2 "vanilla" installation) and specifying a wrong user name (unknown to OCUCS), the IMAP server logs absence of the user, however imapsync goes on to put sync'ed messages into the proxy-admin user's account.
I believe this means that failure to proxy-login as invalid user still succeeds as a proxy-user login. (Or imapsync retries this login, and the problem is there - I'll try to research that possibility too).
If the problem is known to be the Messaging server's one, is there any toggle to disable such logins as the proxy user, and return a failure (i.e. user account absence, password mismatch, whatever)?