HDR not functional

HDR is not working whatsoever. The HDR setting in the game is completely broken. Changing the in-game HDR setting between OFF or Auto does nothing. I have everything set up for HDR on my PC, it works in every other HDR supported game on my PC except this one. I've tried running the game in HDR with both Dolby Vision and HDR10 - neither one works. HDR is enabled in Windows.