I’ve had this problem for years whenever I’m playing the game on LG C1 which I’m often using for HDR in other games. Sometimes when the game is launched at some point after HDR was being used (I play an HDR game, turn it off and Windows HDR off, then launch WoW after some time), I get a washed-out bland cursor and other UI elements such as the interact cogs and everything of that type.
So to be clear, I’m not playing WoW with Windows HDR enabled, the only trigger from what I can tell is that HDR was being used previously at some point, and the PC wasn’t restarted in the meantime. I don’t know if there is a specific amount of time after HDR is enabled/disabled, where the game is susceptible to this, but it does happen pretty often.