Firmware update from June 2020 still NOT WORKING
This was posted to the forum by Comcast in June 2020: "A firmware update was recently deployed to TV Boxes that may be causing picture issues for some customers. The update includes a feature that defaults TV Boxes to the highest screen resolution the TV is capable of. This is causing a black screen, blue screen, a 'no signal' messages, or a "flickering" screen for some customers."
The temporary fix was turning OFF Prefer Best Available Resolution option. I left it this way until this issue was fixed. It's been almost a year now and I decided to turn back on the Prefer Best Resolution option thinking almost a year would be plenty of time to fix this bug but found that this issue was NOT FIXED and causes my TV to lose audio, cause screen to flicker, and finally become white snow.