[Dovecot] POP UIDL

Hi

I run a small mail server with Dovecot and postfix. Several of the accounts are popped by an external email provide I use, mostly out habit and also for a bit of redundancy. I have no details on that external server except that it uses exim.

Lately, it's been repopping mail from accounts (mail is left on the server so I can use IMAP) at fairly frequent, but undetermined, intervals. Before I take it to them, I want to be sure it's not an error on my side. How can I be sure Dovecot does not have a problem with the UIDL list causing this external server to repop the mail?

For the record, I'm not inclined to think it's a Dovecot issue, but since that's the bit I can fix, I'd like to be sure.

Cheers

Simon