Rank is collected every 12h so there can be some ranking shifts in the meantime. Also, we track keyword rankings within all categories only (not within certain categories)
Amazon upgrades the customer experience all the time and that can change rankings from time to time. Also, Amazon uses Personalized search results, so every Amazon user can have slightly different results.
Clear the browser's cache or activate Inkognito Mode to see the non-personalized search results.