Hello,
Thank you for contacting Rank Math and sorry for any inconvenience that might have been caused due to that.
May I check with you, are you using the latest version of the Rank Math plugin?
If you are not, then please update it to the latest version as we have added many fixes and improvements:
https://rankmath.com/changelog/
If you are currently using the latest version, then please check the steps below to make sure that your post/article is set to index.
1. Make sure those posts are not selected as ‘noindex’ in WP > Posts > Your Post > Advanced Tab in Rank Math.
Screenshot:

2. Ensure that the noindex is not selected for Global or Posts meta:

3. Check the sitemap settings and check if the posts are setup to be included in the sitemaps:

Let us know if that resolves the issues.
If the issue persists, please share the affected URL in the sensitive data section so we can help you check from our end.
Looking forward to helping you. Thank you.
Hello,
I have updated the sensitive data as requested. Can you please check further?
Thank you.
Hello. I have done all of the steps provided. All settings were already established the way you said they should be. But it does not appear that anything has changed. Our Sitemap still shows 97 posts. Please advise.
Hello,
I have checked your sitemap and the post_sitemap.xml
contains 112 URLs.
(Check screenshot in sensitive data section)
Could you please clear your browser cache and check the sitemap again?
Please re-submit only the sitemap_index.xml
in the search console and wait for Google to crawl the sitemap.
I hope this helps. Looking forward to helping you.
OK, it seems that either updating RankMath and/or toggling the options you told me to select from on to off and back on again worked. Hopefully Google will pick up in our new posts soon! Thank you!
Hello,
We are super happy that your issue is resolved. If you have any other questions in the future, know that we are here to help you.
If you don’t mind me asking, could you please leave us a review (if you haven’t already) on https://wordpress.org/support/plugin/seo-by-rank-math/reviews/#new-post about your overall experience with Rank Math? We appreciate your time and patience.
If you do have another question in the future, please feel free to create a new forum topic, and it will be our pleasure to assist you again.
Thank you.