Thanks for reaching out to let us know what you're seeing. To help clarify the issue I have a few additional questions:
- When you state that you have to exit to the TV's home screen, then select the HDMI input again, are you saying that the issue does not occur initially, but happens after a period of time viewing the HDMI input device?
- During playback of content, have you tried adjusting the picture settings for HDR playback to see if this makes any difference? (press the * key on the TV remote) Many Roku TVs offer multiple picture mode and brightness settings.
- Could you provide a couple specific examples of streaming channels & content titles that you experience the issue on, as well as an example of your setup from a connected HDMI input device where you observe the issue?
- Are you using any A/V receiver or soundbar in your setup?
Roku Community Manager