If Globals.LoginURL is passed a empty returnUrl  the resulting created friendly url contains 
/returnurl/%20/  - which causes all sorts of funky issues.

"http://test.loyaltepays.com/Home/Login/tabid/98/returnurl/%20/Default.aspx"

This can seen in the following example.

Setup a custom login page and place a copy of the login module on it
Set the Login page in admin settings to point to this custom login page

Open site and clck on Login - when the Login  opens click on the Retrieve Password link.

Then click on the Cancel option on the Send Password page.
The url contains a malformed url like the one listed above.

If you do the same thing with the default login a malformed url is still created but its NOT in friendly format
 href="http://test.loyaltepays.com/login.aspx?ReturnUrl=" 
the returnUrl= is still blank but because the url is not in friendly mode it is less of an issue.
it still technically correct but at least does not break the cancel link.

Westa

Logged it that way in Gemini - yes - hopefully it was fixed in LoginURL which is where the root of the issue lies.

Cheers

Westa