SeoSuiteSitemap not rendering correctly

When I try to use the SeoSuite sitemap, it gets the URLs correctly, but it’s not formatting them as XML.

I read the documentation and the content type is set to XML, but it still renders like this:

If I do [[!SeoSuiteSitemap? &type=index]] it renders correctly, as XML, but the sitemap is empty, which is not what I want.