I think my CX might be starting to lose some brightness, or perhaps it's just window HDR. I re-adjust my white point and brightness every 6 months and now I need to adjust the windows SDR brightness slider to 18 in order to hit 120 nits, whereas before a slider value of 12 was 120 nits. This is with OLED light at 100 running windows HDR.
Do you think you’re running into the reduced brightness in HDR game mode bug from the latest FW? I confirmed it’s real with my i1display, only hits ~500 bits now on my one month old CX.