From http to piwik https

I am using a SSL connection for piwik but my normal website runs without SSL.
Piwik works fine but in the visitor logs piwik is not able to track the site url but the site title. Maybe a bug maybe a problem with my settings?

http://www.site.com to https://www.site.com/piwik --> site url can not be definied
https://www.site.com to https://www.site.com/piwik --> is ok