Issues with Ninja Popups

Hi there,

I had originally posted this issue on the ThemeForest comments section and had been redirected to here by Yeet.
I have a site with the Enfold theme installed, and am trying to use it with the Ninja Popups plugin, so that when the ‘LEARN HOW’ button on the video slider widget is clicked, a popup opens up (see examples here: http://demo.arscode.pro/ninja-popups/open-popup-by-clicking-on-the-link-or-button/). The issue is that when I try inserting the Ninja Popup shortcode into the button caption for the slider and update the page, the slider disappears and some strange code appears in the Caption Text field.

I have provided the link to the page, as well as the credentials (see private content), followed by the steps to reproduce the problem:

1. Log into the site as admin and navigate to the homepage. At the moment there is a slider with a LEARN HOW button. I am trying to get the popup to appear after clicking on the button.
2. Edit the homepage. In the Layout Builder, open the Fullscreen slider at the very top, then click on the Video, then click the Caption tab.
3. At this point, try inserting the shortcode [ninja-popup ID=626]LEARN HOW[/ninja-popup] into the Button 1 label, then save and update.
4. Once the page is updated, the slider has disappeared, and the Caption Text field of the slider will have some additional code inside. The additional code must be removed for the slider to function again, without the Ninja Popup functionality.

If you could please let me know whether this can be fixed, or whether there is some other way to achieve what my client is looking for, I would greatly appreciate your help.

Thanks!
Emma