This is an odd bug where the bnc kicks you out, heres how it works.
I'm already connected/logged into my bnc and i send the following packets:
USER blah blah blah blah
then poof i get this:
[08:05] *  Host disconnected
Once i log back in normally *status pm's me this:
[08:05] <*status> Another client attempted to login as you, with a bad password.
[08:05] <*status> Bad username and/or password.
hope this helps.