Have a Sony VTX-D800U FreeView STB used only for radio (not connected to a TV) these days.
Works as normal on all the BBC stations I tried, but on Capital radio (and other Global owned channels), the audio mutes after about 30 seconds.
Thinking it might just need a re-tune, plugged it up to a TV, so I could see the menu. Did a retune. No difference.
Now I could see what it was doing on screen, on BBC channels when you first select one (say R4) it shows an internally generated picture, then changes to the channel information - just text on a black screen. On Global, I'd guess a different mux, it shows the same internal picture then the screen goes blank, and the audio mutes. If I call up the EPG, the audio returns. But the EPG switches itself off after a few minutes, so not a 'cure'.
Thinking it maybe just a fault, dug out another identical Sony tuner. Same problem.
So it would seem somewhere in the fairly recent past there is now a difference between muxes. All other FreeView devices in the house are OK. But the Sony obviously the oldest of all. The other oldest device I have is a Toppy - but haven't yet tried that.
Seems odd it performs normally on TV, but not radio?