[Dovecot] Intermittent "Password Mismatch" errors

[dan at ipws.com]

Hello -

I have had a problem the last few days with Dovecot reporting
intermittent "Password Mismatch" errors for pretty much every client.
Not all the time, maybe 1 out of every 10 connections.  I cannot
pinpoint where the process may be failing.

I am using a MySQL backend to store user information in, and Dovecot
queries that database directly.  It works fine, but it seems as if
Dovecot has a problem connecting to the SQL server for this information,
instead of doing something smart, it just reports a password mismatch.

I've turned on debugging and verbose logging, but I can't see exactly
*why* the process fails on occasion.  MySQL is tuned appropriately, and
there's no reason why Dovecot cannot connect to the server.

I'm wondering if anyone has seen this, and if so, what they've done
about it.  Because honestly, I'm lost.

Thanks
-dant