Shared Theme Question (D7)

So i am working on multi-site with a single drupal 7 core installation. There are total of 5 sites and two themes.  Four of the site share the same theme(template.php) that is located in sites/all/theme/template.php and  one of the site has it’s own template and it’s located in sites/domainname.com/themes/ts2/template.php file.

When loading “domainname.com” site, I noticed that the “_preprocess_html” function in both template.php files are executed even thought the shared theme is disabled from the admin page  for  domainname.com site. Is this expected behavior? If so, what steps should I take only the preprocess_page in the all/theme dir is not called?

Thanks

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