https links in sitemap_index.xml to page-sitemap.xml and others

I have noticed all recent installations of Yoast SEO are creating https links in sitemap_index.xml to the sub sitemap files e.g. page-sitemap.xml and others even when the site has no https function.

This in turn means when you follow the automatically generated links to to the page sitemap e.g.
https://www.domain-name.com/page-sitemap.xml
you get an https warning that the site has no https valid certificate.

I cannot find anywhere in the plugin to tell it not to generate https links in the sitemap_index.xml

Can anyone please advise if this is by design or a bug?

I have read all the articles from people who genuinely have https pages and these do not relate to this issue… it is only appearing in the sitemap_index.xml file where Yoast generates links to it sub sitemap files such as page-sitemap.xml and posts-sitemap.xml etc

Any information would be greatly appreciated.

Thank you

Ramps.

https://wordpress.org/plugins/wordpress-seo/