Airpods Pro 2 behaving strangely with LG G3 TV

Have long used AirPods Pro to watch shows on LG G3 TV with no problem. This TV has the ability to connect to two Bluetooth headphones at the same time, which we use regularly for nighttime viewing. After the AirPods Pro died recently, I upgraded to AirPods Pro 2.

Since then, I've noticed that when watching with just one pair of APP2 connected, the sound is a lot quieter and the TV displays a volume scale that seems to go from 0 to 100 – and I need to increase the volume to about 60 to get them to the point where I can hear them properly.

Occasionally the APP2 sound becomes crunchy and staticy, like crunching a bag of potato chips. When I back out of the currently playing show (eg Netflix) and then start it again, the sound is back to normal, although after a few minutes the crunching often returns. But the headphones work beautifully in every other setting (eg connected to phone and iPad).

NOW: When we connect a second pair of headphones (AirPods Pro) to the TV for nighttime viewing, the experience is perfect – the sound quality is louder, and the TV shows a volume scale that runs from 0 to (I believe) 30. In this mode, a volume of 5/30 is plenty loud and everything is crisp and clear.

I have been racking my brains to understand why the same headphones perform differently when they are the only headphones connected, versus when they are one of two connected. I'm wondering whether in single headphone mode they may be trying to map the Dolby Audio surround sound from the TV onto the headphones' Spatial Audio, but failing to do this properly – whereas when the second APP is connected, both units revert to a straight stereo mix.

I recall reading that the Apple TV 4K can't handle two Spatial Audio devices at once, so am wondering whether the TV is having the same problem but doesn't realise it as it does not natively support Spatial Audio.

Has anyone else had this experience? Would welcome any suggestions. Otherwise the APP2 are working great.