Wordpress updates itself automatically on your website but may not update itself the moment that an update is available.
If you manage your own website and you discover something is behaving oddly it is always worth checking Wordpress’ Changelog to see if a recent change may have caused this – and make sure you are also using the very latest version of Wordpress.
Wordpress is not infallible – sometimes a release can cause an issue and require a hotfix, so you may need to manually update it in order to resolve the issue.