Cloudflare may cause the XML Sitemap or Google News sitemap to be cached for a certain time, presenting stale sitemaps to both visitors and search engines crawlers. This can cause unexpected delays in indexing or worse: old news to be fed to Google News.
So if you are using Cloudflare to speed up your site. Please make sure that at least the /sitemap-news.xml URL is excluded from CDN caching. If you experience slow indexation, try excluding all sitemaps.
Instructions on how to exclude specific URLs can be found at Cloudflare support: https://support.cloudflare.com/hc/en-us/articles/200172316-How-do-I-include-or-exclude-a-specific-URL-from-Cloudflare-s-page-rules-
Try one of these patterns:
/sitemap-news.xmlshould exclude the Google News sitemap;
/sitemap*.xmlshould exclude all sitemaps.
Then set its corresponding Page rule to Bypass.