Hi!
The issue is caused by the script deferring. I noticed on the page source, that all of the scripts are loaded as “deferred”, except some of the ajax search pro scripts. If you are using WP Rocket or similar cache optimization plugins, make sure not to exclude the plugin files from the defer process.
Also, usually excluding jquery from the deferred scripts helps with any compatibility issues, but it should not be neccessary.
You can also try this compatibility switch, if nothing else works: https://i.imgur.com/7pw4sjS.png
