[wp_paypal] Not Working

Using the [wp_paypal] shortcode does make the payment button appear, and it seems to have all the necessary hidden fields. However, pressing the button results in being redirected to the same page with a ‘#’ on the URL.

I’m getting no errors or debug logs, but due to the nature of the issue, I suspect that the script that disables the default button behaviour and enables the PayPal payment hasn’t enqueued. I am using PHP to add the shortcode through ajax:

$shortcode = '[wp_paypal button="buynow" name="' . esc_attr($session_title) . '|' . implode('|', $passed_values) . '" amount="' . number_format($total_due_today, 2) . '" button_text="Pay Now - £' . number_format($total_due_today, 2) . '" return="' . $success_url . '" no_shipping="1" description=""]';

In the settings for the PayPal checkout, there’s an option for loading scripts globally. Is there a way to do this for the standard payments too? Or is there a chance that something else might be happening here?