Consistent Navigation requires that a main menu, search bar, or other repeated navigation block appears in the same order relative to other repeated content every time it shows up across a site, unless the user deliberately changes that order themselves.
This predictability lets screen reader users, and anyone who has memorized where key links live, navigate efficiently by muscle memory rather than re-scanning a rearranged menu on every single page. Section-specific navigation that reorders itself between templates is a common way sites fail this criterion.