Hi Patricia,
I did everything…went the hard way and deactivated all plugins, then installed a blank WP instance. It all didn’t work.
Then I found out the problem:
I used iCalendar to import the ICS file from Google and not Google Calendar. I’m still not sure why venues are not imported when you take the iCalendar import, but that’s the reason.
As soon as I used Google Calendar as Source for the import I see the venues again.
So thanks again for your help!