AFAIK supl.nokia.com doesn't use SSL, so nothing to do with certificates.

Before 1.3.1 I had never tried supl.google.com, always had supl.nokia.com and got a fix pretty quickly, although I have to say that now that I've switched to supl.google.com the fix comes a bit faster.

Still no idea if there is a cause-effect relationship between 1.3.1 and supl.nokia.com not working.