I rebooted the main offending laptop (connected via power-over-ethernet) and fired up another (connected wirelessly).

Both were set to play Radio 4.

Both have now been streaming for over 19 minutes (timed using the counter at the top of Control:PC) without interrupt.

So, no, it does not appear to manifest playing channels.

Do you have a hypothesis?

In the spirit of Spinaltap, I would like to confirm that I am not involved in the corrupt theft of a global sport.