Main Index Template (index.php) is saving to /images/ subdirectory of theme

I have many installations of WordPress for my clients, and have only had this issue on one client account.

When I go to Edit Themes and select the Main Index Template (index.php) and make my edits. I click Save and can view the change in the admin page.

The changes do not show up on the live site. And upon further inspection, the file /wp-content/themes/themename/index.php is not updated on the server.

Even if I log out and then log back into the Dashboard, I can see the updated file in the Admin page, but if I view the file on the server, it’s the old version.

Any ideas how I can further troubleshoot?

Also, I tried editing the footer file, and that updated both on the server and the admin panel, so I’m really baffled now.

I have checked the permissions, and it’s the same for all the theme files. (-rw-r–r–)

Any help would be greatly appreciated.

Thanks!