I have exactly the same issue. I’ve changed My audio setting from Dolby to pcm but to no avail. Googling the issue it looks like BT customers had a similar issue themselves in 2017. I’ve never had an issue with recording the various BT Sports channels previously and given we are paying extra for the privilege of accessing these channels I hope Virgin tackle Bt about it.
This is good guys, the more information we have the easier it is to track the fault.
So far we know:
It's something to do with recording from the channel
Replacing the box doesn't fix it
It didn't happen last football season
I for one only record one thing at once, where the box can record/use six tuners, right? So, I don't think it's incoming bandwidth or something out of scope of the tuner. It could be latency on the drive, so write speed on the drive or throughput on the controller not keeping up with the amount of data UHD is throwing at it. None of us seem to lose picture, just sound, so are Virgin using a new/different MPLS or setting, or have they moved away from MPLS to old fashioned straight packet transmission (not sure why you would though)? Packet loss through an MPLS should lose the whole packet, not just the sound element, as it doesn't "know" what it's transmitting. Or, conversely, have they moved to MPLS and the chip in the box can't decode then write out fast enough? Switched from TLS 1.2 to UDP maybe, to keep up with the larger amount of data transfer ("I'm sending a thing" "OK" Have you got the thing?" "Yeah." vs "throwing a ball and hoping someone catches it" which is much faster but less accurate)?
Spitballing, but if something works (i.e. the football last year), you change something and it doesn't, go back to the thing you changed and check it out.
Thanks for contacting us over the Virgin Media Community although we're sorry to hear that you're having some issues with the sound on recordings for the BT Sport UHD channel.
We've investigated this with our support team and this fault has been raised under the reference F007309920.
This should only affect recordings from the UHD channel; Live TV streams and other BT Sport channels are unaffected.
Thanks for your continued patience whilst we get this resolved.
This problem does affect live streaming. If you pause the live streaming and then press the play button to start watching again, the sound problem is there. To overcome this you have to fast forward to the real time live streaming - which means you miss viewing part of the program.
Just to add my name as someone affected by this. I haven't got a 4k TV, but use the 4k channel for the better picture. I usually watch the football live, and have no problems, but watching the recording from Saturday shows the issues mentioned in this thread. I will use the HD channels in the short term, as I don't always watch live, and do occasionally wish to pause, even if watching mainly live.