Sorry for the confusion. We did check on the search page link you provided and do see that a noindex tag isn’t present in the source code.
If you have already confirmed that both Yoast SEO and WordPress are up to date and the issue is still occurring, we would next recommend performing a conflict check to determine whether another plugin or theme is interfering with the Yoast plugin.
The fastest way to do this is to?deactivate all non-Yoast plugins and switch to a standard theme?like?Twenty Nineteen.?
Test this on your development or staging site, if you have one. If not, we recommend using the?Health Check & Troubleshooting?plugin. This plugin allows you to run a conflict check?without affecting normal visitors to your site.
As we can imagine that you’re unfamiliar with checking for conflicts, we’d like to point you to a step-by-step guide that will walk you through the process:?How to check for plugin conflicts.
If you do not feel comfortable to do this yourself or if this does not solve your issue, our Yoast SEO Premium plugin comes with one year of (technical) support.