Domain-restricted Vimeo video in Video Block loading in frontend but not CMS

I have a domain-restricted Vimeo video that is embedded via the default Video Block. On my test server (for which the video is restricted) it displays ‘Sorry, Because of its privacy settings, this video cannot be played here.’ in the panel however loads fine in the frontend. Is there an obvious reason for this? I guess the way it’s embedded is different, possibly a bug?

An issue has been created for this: