The way the localized variation path is created is:
1. find the current page language root path: /content/snam/language-master/it
2. replace /content with /content/experience-fragments: /content/experience-fragments/snam/language-master/it
3. append the relative fragment variation path: /site/footer/master/jcr:content: /content/experience-fragments/snam/language-master/it/site/header/master/jcr:content
The fragment content doesn't exist at this location, so it is falling back to the original reference.