In fact yes, the popup was the issue, thank you for this!
I had to change and create a different page structure to accommodate the "Submit Review" shortcode on the page itself rather than in the popup.
Since MetaBox is supposed to be compatible with Elementor, I think you should work out a fix for this issue because having too much information (elements) directly on the page make it load slower whereas when we were using the button, the form would only load when a user clicks the button... But thanks for pointing the issue anyway and hope you can bring a fix to this issue in a near future.