Hello,
I’m sorry to hear that your latest posts are not appearing on the HTML sitemap created with Rank Math. This issue could be due to custom canonicals in the sitemap. When custom canonicals are added to posts, they may not appear in the sitemap.
To ensure that all your posts are shown in the sitemap, you should remove the custom canonical from all your posts. By doing this, you allow Rank Math to generate the canonical and include all your posts in the sitemap.
If you need further assistance or have any other questions, please feel free to ask. Thank you for raising this concern.
Closing spiel.
Sources:
How to Create HTML Sitemap Using Rank Math » Rank Math
Rank Math Sitemap Issues and Their Fixes » Rank Math
As far as I am aware I have not set any custom canonicals.
Hello,
Thank you for contacting Rank Math support.
Please navigate to Rank Math > Sitemap Settings > Posts and make sure that Include in HTML Sitemap is enabled.

If this is already enabled, then please share the URL of your HTML sitemap with us so we can investigate further.
Thank you for choosing Rank Math
Hello,
Thank you for contacting Rank Math support.
Please navigate to Rank Math > Sitemap Settings > Posts and make sure that Include in HTML Sitemap is enabled.

If this is already enabled, then please share the URL of your HTML sitemap with us so we can investigate further.
Thank you for choosing Rank Math
Hello,
We can see that the posts are showing on your HTML sitemap page.

Regarding your latest posts, please follow the steps in this video to flush and regenerate your sitemap: https://i.rankmath.com/pipRDp
Let us know if that helped
That worked! thank you so much!
Hello,
We are super happy that this issue is already resolved. If you have any other questions in the future, know that we are here to help you.
If you don’t mind us 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.