[Dovecot] Hang on login since 1.2.4

I upgraded a number of servers to Dovecot 1.2.4, and now suddenly I get a lot of customers saying it takes a long time for them to log in.

I enabled all debug and see the following:

Sep 01 10:49:18 auth(default): Info: client in: AUTH 10
DIGEST-MD5 service=pop3 lip=195.41.131.35
rip=111.111.111.111 lport=110 rport=3730 Sep 01 10:49:18 auth(default): Info: digest-md5(?,111.111.111.111): Invalid realm: example.com Sep 01 10:49:25 auth(default): Info: client in: AUTH 11 PLAIN
service=pop3 lip=195.41.131.35 rip=111.111.111.111
lport=110 rport=3730 resp=<hidden>

Basically there is a lag of ~7-9 seconds upon login, this seems to be consistant across the servers.

Any help would be greatly appreciated.

// Tom