IIRC `appstreamcli validate` is preferred over `appstream-util validate`. Nevertheless, you're right, the file has an error in it. I've just corrected it with https://commits.kde.org/plasma-sdk/d5f44659ae4119879326646bfb2570232946180b. Would you be able to regenerate the AppStream data in openSUSE with this commit included? Thanks!