You might be interested in
this thread, which describes a way you can remove those, or alter them to your own mapping, though at a great cost. (The display at the bottom will not show any useful page information, and you won't be able to skip around in the book by inputting a page number.)
I think it would be great if calibre included a structure-detection algorithm in its conversion-to-epub process that allowed for automatic creation of a page-map.xml, which, in the extreme case, could be use to remove such "pages" altogether, but it's probably not a high priority, and officially,
Adobe says we're not supposed to customize these (bad bad Adobe--you can do it but we can't? what happened to Open standard?), and doing so will make an epub fail an epubcheck.