It is becz they converted to sdr feed to fake hdr.For namesake they did that saying that they are providing in hdr.
Unless they changed to sdr the colour will not be accurate
Bro, I had a TCL 4k 55inch TV during the World Cup and I played sky sports main event UHD channel in it. I also got low brightness, I reset the TV's picture settings to HDR channel and after that I saw a lot of difference