HDR to SDR conversion is broken on older hardware and external displays?

Since the latest updates, videos in Fotos app just show up strange on non HDR screens, for example I have a iPhone 13 mini and my wife a 13, we take videos with them for a while now. Also have an iPad 7th gen where the videos used to look normal, same as on the iPhones. Now the videos on the iPad just look too bright, thumbnail is one but when I open the video, even older ones that used to be ok, just look tooo bright. When was this changed and why??