The Witcher 3 just can’t seem to function properly on the PS4 Pro- first, CD Projekt RED simply didn’t want to put out a PS4 Pro enhancement patch, then when they did, it lacked HDR functionality. Then the HDR functionality was added in, but it ended up breaking just about everything else instead. At some point you have to wonder what is going on.
What is going on is that CD Projekt RED has indicated that it is listening to the complaints about the issues brought on by the HDR patch, and that it is looking into them. Speaking on Twitter, the developer noted the issue was something that it was aware of, though they did refuse to give any specific time frame for when fans might expect it to be fixed.
Until then, all I can say is try playing the game with HDR functionality disabled on the PS4 Pro, I guess. The Witcher 3 is out now on PS4, Xbox One, and PC.