Hi Sue,
I understand the issue. This happens when the theme does not “execute” the shortcode. WordPress will run the shortcode only when a function like do_shortcode is called on the content.
In this case, I see the “post excerpt” is not checked for shortcodes.
You will see this behavior for any shortcode.
Can you please send an email/raise a support ticket with the theme developer and ask them to execute shortcodes?
If in case, the theme developer does not respond, please share create a temp admin user account and share it’s detail with me in the contact form below. I’ll login to the site and see if I can make any changes to the theme/see if there is any workaround.
Contact
Thanks,
Aakash