Color tags for pages in the Pages palette do not shift when the page order is changed due to changes in the text flow. Changes in text flow can add or remove a page automatically. A certain headline, for instance, then can move from page 19 to page 20. I wanted to tag the page that holds this headline. When text flow adds a page, the headline is moved from page 19 to page 20, but the color tag is still shown for page 19. It is not “linked” to the page content.
This behavior is different from adding or deleting a page manually. In those cases the color tag moves with the page content it was assigned to (which make more sense for me).