Is it a bug, or is that what Roku finds to be their default gamma now? I used to have it set to 2.4 for about a year but changed it back to 2.2 months ago. I noticed my backlight settings were different in SDR so I checked the expert settings and noticed it was changed back to 2.4 in SDR and HDR, and most likely Dolby Vision (but have not checked). I have the TCL R617 from 2018.