The template is Melvin.
On a dev server I've upgraded a client site from J3 to J4 - almost eveything is working, except the modal feature found in SP PageBuilder. Every page on the site uses this feature, especially the 'Abot' page linked below, for contact methods.
https://www.cmtekwerx.com/carls/about
I use Balboa forms for the popups, with shortcode, but on the 'About' page I've also included three default modals to show it's not the add-on that's causing the issue. This is a NEW migration from J3 to J4, and all extensions have been updated to the latest, as has the Melvin template.
This website makes HEAVY use of the modal feature on all pages, and it's imperitive that it works. I've exhausted everything I can think of to get it to work.