Class constructor MyView cannot be invoked without 'new'

Dear community,

since a couple of hours I am seeing this error in my browser (Chrome 67):

custom-elements-es5-adapter.js:4 Uncaught TypeError: Class constructor ScheduleView cannot be invoked without ‘new’

Does anybody know this error or maybe has an hint?

Best regards

P.S.: I am using Vaadin 10.0.2.
17196834.log (40.2 KB)