A WordPress 5.5 sitemap bug was reported that affects some sites with native WordPress sitemaps. The bug creates non-existent XML sitemap pages. The issue has been officially confirmed.
Sitemap Pagination Bug
The WordPress bug affects websites sitemaps that are generated by the WordPress core. The bug affects websites that have so many pages that they need more than one XML site map.
According to the bug report, the sitemaps can look like this example:
But when you click on the post-2.xml or post-3.xml link…