Facebook app link not redirecting to Facebook canvas page

Launching my canvas page Facebook app is driving m开发者_如何学Goe crazy. When I posted it's link (http://apps.facebook.com/digitalhitcelebrity) to a fan page wall the FB "attach link" button grabbed the app's callback url (http://www.digitalhit.com/celebotd) instead.

The strangeness occurs here: if you go to the the callback url when NOT logged in it redirects you properly to the canvas page. If you go to that url when you ARE logged in you don't get redirected and the page is not framed by the Facebook branding.

Using the new php-sdk. Any ideas?