An error occured after activating theme "zeitgeist" in plugins

Support & Bugs
1

this happened after installing 2.17 but it’s only perhaps in context with 2.17. It seems installation was successful.
Activating a new theme in plugins and choosing “Zeitgeist” theme an error window appeared.
After installing 2.17 manually (binary) all folders and files the same error messages appear.

  1. Variable “debugTrackVisitsInsidePiwikUI” does not exist in “_piwikTag.twig” at line 3

  2. Template “@CoreAdminHome/_menu.twig” is not defined in “admin.twig” at line 34.

Apps on mobile devices are ok (database ok)

Anyone a solution?