Thread:Project:Support desk/Changes to VectorTemplate.php only appearing on special pages

I've made some modifications to the VectorTemplate.php page. I can see these changes on pages like the purge cache confirmation, Special:Version. I can see these changes when I'm logged in under my own account. However, I cannot see these changes when I visit an article page as a logged out user.

Can someone give me some pointers on where I should look for debugging this? I've tried things like removing the skins folder entirely (I get an error) so I know that it's using the skin, I just can't figure out why the changes are not appearing.

I'm using: Mediawiki 1.25.1 MariaDB PHP 5.5.25-1~dotdeb+7.1 running via php-fpm Nginx