@tmm1 I’m seeing same problem, exactly as described by @Maximus.
I’m in Sydney Australia and so far I’ve seen the issue on a couple of programs on our two public broadcasters, that is ABC and SBS. It’s a little elusive as not all shows have AD (Audio Description) broadcast, only certain shows and usually during prime evening hours (or repeats).
Last night I saw it again on a show called “Backroads” on ABC at 2000-2030 for example.
I’m a longtime Channels user on ATV and this problem only started in a fairly recent update to Channels I think, as I mainly watch ABC and SBS and it was not an issue over last couple of years. I’m mainly using an HDHomerun Quatro (DVB-T) on my ATV 4K, but I also have a couple of legacy HDHR3’s (DVB-T) that I quickly enabled on Channels last night and pretty sure issue is apparent on those as well?
I can confirm the only Audio track shown in pull-down Settings during these broadcasts is the AD one, and thus if you turn it off you get NO Audio at all ...
Please advise how I can capture what you need to trouble-shoot? No Channels DVR here obviously, only live TV.