Am watching a film on 136. Good signal. At 2300 hrs, recording starts on channel 135 as programmed.
Channel 136 then breaks up, with warning 'NO OR POOR SIGNAL'. Film now impossible to watch. Can anyone explain this phenomenon which has occurred previously?

Which box and how many cables have you got if it's a hdr ?

If an hdr what sig strength and quality for both tuners does diagnostics report