In Slovenian wikipedia we use in our infoboxes a lot of data from Wikidata. When I try to change the contents of the parameter (for example image parameter) that collects data from Wikidata, clicking button "Apply changes" in template dialog box does not show any changes. You can test this in slovenian article sl:Stanley_Kubrick.
Topic on VisualEditor/Feedback
This is a known problem. Unfortunately, it's a very difficult, fundamental problem.