Works fine in posts, but can't get it to render in PAGES

Hi – I love this plugin and have been using it for awhile, however I can’t seem to get the php include to work on any PAGE that’s using my default page.php template. It seems to work on most pages that are using a custom page template (but not always). I’ve compared the code and don’t see any differences that would be causing it not to render sometimes. Any ideas? I just can’t figure it out. Makes no sense why it works in some places, but not in others.

Here’s an example of a default page where the include just won’t render, I’m calling [php function=15] – https://www.abn.org.au/thank-you-copywriting-mini-course/

Here’s a post calling the same include: https://www.abn.org.au/business-resources/achieving-effective-website-content/ (the bit at the bottom above author that says “You might be interested in this event”)

https://www.ads-software.com/plugins/allow-php-in-posts-and-pages/