Help With HDR Strange Problem

I went to play Forza 7 in HDR  on the Samsung ku6000 and im getting strange pixels there neon like red & blue allover the screen.

I have tried all the different settings on pc ycbcr 444 422 420 10 bit & 8 bit they all do the same. I have also tried RGB 444 full & RGB 444 limited these settings dont show the funny pixels but as far as I know you cant use RGB 444 & HDR.

 

HDR works fine with same tv & HDMI cable from ps4 pro anyone know whats going on im confused thanks in advance...