Plugin issues with customiser menu editor

Hi,

This plugin is blocking the load of menu elements in the customiser.
I can see the following error in the console:
quick-add.min.js:20 Uncaught ReferenceError: pltVars is not defined
at HTMLDocument.<anonymous> (quick-add.min.js:20)
at i (jquery.js:2)
at Object.fireWith [as resolveWith] (jquery.js:2)
at Function.ready (jquery.js:2)
at HTMLDocument.J (jquery.js:2)

The same type of issue happens also with the WP Real Media Library plugin we are using. It looks like page links to is loading jquery libraries that are incompatible with some other plugin or themes?

Thanks