It may be that you have an old copy of the theme? We deleted all the handlebars templates from adapt-contrib-vanilla back in May (v2.1.0) so that only the versions in the core framework would be used.

If you still have a copy of these files in your theme then they will be overriding the core framework versions.

Specifically it's partials/component.hbs that's important. If you have a copy in your theme and you haven't changed it, either delete the theme's version or update it to be the same as the framework version.