[accobra427]

And another thing I don't have an HDR tv so the settings in windows are of by default so i don't think that's the solution.

 I'm having the same issue. My TV is 4K but doesn't support HDR. Anything I play with HDR is too bright and washed out.  

Do you want to know an ever weirder thing.... i do have a 4k tv with HDR as my main computer screen, so i installed kodi 18 on that one and hocus pocus 4k movies are running just fine. So i don't think it's a bug in the new update. 

Just curious what OS are you running? my HTPC is running Win 10 Enterprise and my main computer is running Win 7 so it can be a bug with Win 10.