Hi,
It is an issue with WP Rocket, it adds a function scope around localized scripts (for late loading), however it completely breaks the variable scope, and those variables are unusable if the timing is incorrect. I am seeing multiple issues caused by that on the error console: https://i.imgur.com/A3QFXbK.png
Try looking for an option within WP rocket to disable javascript deffering or some sort of a late js loading feature, and turn that off.