The highlights aren’t blown out on the UHD; they just look blown out because of the tone mapping. The only way you can tell if highlights on a UHD are blown is if you look at the image before the EOTF is applied. Otherwise, it’s likely that the tone mapping clipped or compressed the highlights because your display cannot get as bright as the Dolby Pulsar it was graded on.
This is one reason why Dolby Vision (and maybe HDR10+) are coming on newer releases; it has additional meta data to allow the colourist to specify how the image is to be presented on displays that cannot reach the brightness necessary to properly display the picture.
This post has been edited.