I created a template for my client and assumed that in 2013, it would behave as it did in previous versions of PowerPoint: when launched, the read-only file could only be saved as a new .pptx document. But this template launches as the original .potx and allows edits to the template itself. Also, when a cover page is deleted from the document, the master it is based on is also deleted, making it impossible to add a cover to a document that is missing one by simply changing the layout from the ribbon.

What's going on? How can I fix this?