Missing urls in sitemap

Hi guys,
I think there’s a bug in sitemap generation that causes missing urls.

I’ve hidden a post type from search result (on left-hand side menu, under ‘SEO’ > ‘Search Appearance’ section), so all these posts are obviously excluded from sitemap. This is ok.

But if I change the ‘Allow search engines to show this Post in search results?’ to ‘Yes’ in the Yoast SEO metabox for certain posts, they are not included in sitemap.

Is this a bug or am I missing something?

Thank you!