AJAX is coming from WooCommerce so GP doesn’t control it.
You can see it working with GP here:
I would recommend making sure you are using the latest version of theme and premium plugin
Then try disabling all non-GP plugin and see if there is a plugin conflict.
If that still doesn’t help, then switch to a twenty series WP theme and see if that works.
If it still doesn’t work then you will need to report this to WooCommerce as it’s their feature 🙂