Chouby and Dobbydoo, thanks for the advice.
When I corrected the wpml file the strings showed up in the backend. I needed to save some theme settings again and then the translations for the homepage_featured_headline showed up. After a lot of refreshing the English version of the homepage_subheadline showed up, but it doesn’t change anymore when I switch to German or Dutch.
I’m not using the homepage_headline and the homepage_featured_headline seems to change properly switching languages. Only the homepage_subheadline doesn’t. It seems, it doesn’t get loaded every time.
Any suggestions here?
Thanks!