The horizon box toses the sound for about one to two seconds (and somtimes the picture flicks to another channel during this). Sometimes it happens once every 2-3 minutes sometimes every 20-30 seconds. It happens with normal TV and recordings.
I have tried switching off & on, factory resets, energy saving mode / normal mode, swapping the TV and it doesn’t help.
If I replay the section (live or recording), it is usually ok. Thus I assume it is the Horizon Box that has the problem and not the connection. Any ideas?