I have switched the js source on the search compatibility options submenu to “Minified Scoped”, that way this 3rd party plugin issue is resolved. Please note the other plugin developer, because this error may cause malfunctions in other plugins as well. I'm sure it wasn't intentional.
The search preview should work now. Please note that the preview might differ a bit from the actual result, as some stylesheets from the theme might not be loaded on the backend.
I wish you a successful and happy new year!Best,
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