Please check the Category Posts Plugin’s Changelog on WordPress.org (on the Development tab). I’m providing the screenshot below:
You’ll notice that version 4.9.13 was indeed updated on JULY 22 2021.
4.9.13 – JULY 22 2021
Fixed Line number with WordPress 5.8
However, on the right side it shows: Last updated: 1 month ago.
This last update doesn’t refer to updates to the plugin version itself, rather updated information on wordpress.org that it was Tested up to: 6.1.1.
I’ve dug further down the source code to the last commit of the plugin files, and you can see that the change was only made on the readme.txt file and it’s just the Tested up to: 6.1 part:
WordPress.org’s plugin listing page is generated from this readme.txt file. So what WordPress.org is referring to when it says: Last updated: 1 month ago, is only this much.
So you see, there’s no significant update and there’s no actual disagreement about the update date.