Sorry, I never use Insert > Page Numbers > Format Page Numbers to pick a section. I go to the section where I want to change the page numbering and format it there. The links I gave you should tell you how to format your sections and handle the page numbering. I'm sure you have not read them yet.

Every section has three headers and three footers. It may have a separate kind of page numbering. It is possible to have page numbering be different in different headers and footers in the same section. A single page can have multiple sections. I suspect you have a page with more than one section.

I gave you those links because I have to get back to my paying job and thought you could use them to find your answer. Glad you figured it out.