Thank you, I have found the issue and made a correction to one of the plugin files as well as the configuration.
To make the change to the live server:
– Copy the wp-content/plugins/ajax-search-pro/includes/classes/etc/class-asp_helpers.php file from staging, as it was changed
– ..and also, change the advanced content field like so: https://i.imgur.com/E0wDSGT.png
That will resolve the issue