HomePod stereo pair making clicking crackling noises when connected to HDMI (ARC)

I had a problem with HomePods (not Minis) making clicking and popping sounds when playing back audio from my Samsung TV. It sounds like radio interference and doesn’t occur until the speakers have been in use for a couple of hours. The Homepods are connected to an AppleTV 4K and the Apple TV is connected to the Samsung TV by ARC HDMI port.

Other posts suggested decoupling the speakers which work as a stereo pair, then removing them from Apple Home, then reinstalling and then re coupling, all of which I have tried. I found that whilst the HomePods were running 16.3.2 the AppleTV which they also serve, was running 16.3.1. so I've updated that to 16.2 as well.

Initially the problem was cured but after two days it has reoccurred.

Any ideas please