Template pattern doesn’t update across site

After a fresh WordPress installation, I created a blank theme with the Create Block Theme plugin, then added a template for all pages. The template was applied retroactively to the “Sample Page” page, but I created new test pages as well. When I update the Header pattern, the changes are reflected on “Sample Page” but not any of the other pages. They retain the header styling from the last time the page was updated and saved. The only way to get the header to update on those pages is to make a trivial change and save them. Will I have to do this to each and every page every time I update the header? Is there an easy fix I’m missing?