I give up...please help regarding wp-login.php redirect

For some odd reason, upgrading the Magazine theme to threaded postings has fixed this issue, which is odd because I didn't have to update any other themes.

Any idea why this was the case?

I noticed that the updated wp-login.php directed the user to a url that had a lot of "%" symbols in it, whereas the original did not (just the direct url). What does that indicate?

Regardless, it seems to be fixed.