I'll find the rewrite rule in my apache config file, right? Or do ezPublish have a rewrite rule hidden somewhere in the .ini settings?
I've created a guest account so you can see this behaviour live:
URL: http://www.kompetanseportalen.no
-u guest -p guest
when you log in first time, all is well. But try to click the "logg inn" symbol (the key) to the left, then click the lowermost link in the next page, the one under "Innlogging for andre brukere", and log in again.