are you using any Optimization plugins or server side optimizers ? As they can sometimes create different ‘cached’ combined/minified files for Logged in and Logged out users. Check to see if they are causing an issue by temporarily disabling them and clearing browser caches.
Hi David, you are right, by deactivating Autoptimize, the issue with other issue is gone. I located the issue to be with the Aggregate JS-files setting, which should be off.