Registration redirect to main site

HI I have thepodnergroup.com mapped to mmtblogger.com
when I try to register on the podnergroup.com I click the register link below the login form and I an redirected to mmtblogger.com to register, this is confusing for me because I would think the link to register would stay on thepodnergroup.com com and not redirecting to mmtblogger

am I the only one that has experienced this

thanks
steve