Removing Chapters Numbers from Page Numbering

[Luxanais]

I've been working with a template that at one time used chapter numbers in the page numbers. They have since been removoed, with the exception of the last page, the Index. If I deselect Include chapter number in the Page Number Format dialog, the chapter number dissapears, but when I update the document

(CTRL + A, then F9), the chapter number comes back.

Any suggestions on how I can permanently remove the chapter number?