Has anything related to how URLs are routed or redirected changed in 1.26?

I'm being told that the configuration to enable short urls in IIS7 is partially broken now. Any title with a : in it (including special pages) is getting into an infinite redirect loop like:

http://example.com/wiki/Special%3ASpecialpages -> http://example.com/wiki/Special%3ASpecialpages http://example.com/wiki/Special%3ASpecialpages -> http://example.com/wiki/Special%3ASpecialpages http://example.com/wiki/Special%3ASpecialpages -> http://example.com/wiki/Special%3ASpecialpages http://example.com/wiki/Special%3ASpecialpages -> http://example.com/wiki/Special%3ASpecialpages ...