The Roku is auto detecting an HDR capable display, but since the TV is not HDR capable, everything is very dark and there are other color and blur issues. I manually changed the Roku display setting to 4K 60hz and the problem was solved. But the Roku is changing it back to auto detect so the problem is recurring. Is there a way I can prevent Roku from switching from my manual selection back to auto detect for the display?
Problem still persists when I have the Roku plugged directly into the TV. Results are the same regardless of whether the Samsung "UHD Color" setting is set to On or Off on the TV, which was the Roku support team's first suggestion. Samsung doesn't claim the TV to be an HDR TV, but maybe UHD Color is the same concept? I'm not up on current audio/video terms and technologies.
I had something similar resetting our 4k to 1080. Try turning off auto-recovery with the secret code 5X Home, Down, Left, 3X Up After that, it should stay where you set it and not keep popping back to auto.
@klambert THANK YOU! I had no idea those secret codes existed. I normally had to wait a few hours for it to revert, so I won't know for certain if it worked. But that sure looks like it will solve my problem.