if it makes you feel better, I see the same issue on windows. It's not your series X. Bungie actually had the same issue with Nessus in the past, and they patched it with v2.1.0.
See these links:
https://youtu.be/sAMKhgbN9lM?t=405
https://www.bungie.net/en/Explore/Detail/News/47462
We might just have to wait.
It kinda does, actually. Thanks. At least now I know I'm not imagining it. I was fairly certain it's not a hardware issue given that the problem exists on Xbox One X too, and no other games are having issues with HDR on the Series X.
Hopefully it'll get a fix with the next gen visuals update in December.