Glitch with Elementor shortcode widget

The Profile Builder Pro shortcode doesn’t work in the Elementor shortcode widget.

I spent half the day trying to work out why, when a user tried to register on one of my sites, they got the message that the username and email address were going to be used soon, Please try a different one!

A bit of investigation using Google led me to the fact that the form was being submitted twice as the user would correctly appear in the users table.

The general consensus on Google seemed to be that the most likely cause was a plugin conflict. I disabled every plugin on the site except Elementor and the problem remained. I then created a new login page, using the normal block editor instead of Elementor and it worked as it should. I reactivated all the plugins that I had deactivated earlier and everything still worked.

My problem now solved so I am only posting this here in case someone experiences the same thing at some time in the future.