Many skins use in stylesheets/content/common.xsl the variable $site-uri-prefix and $site, but without importing workspace:web://stylesheets/variables.xsl

This is a mistake of the skins, and leads to a XSL error since the fix of CMS-9194 (protocol view:// look at locations in the wrong order).
The bug was hiding this error.

To solve all skins without migration, the XSL workspace:web://stylesheets/variables.xsl should be imported by plugin:web://stylesheets/content/common.xsl