LG did not enable the AudioEDID for LPCM 8 channels, just the standard LPCM 2 channels. The LPCM 8 channels are very important for multi-channel audio from game consoles and PCs because not all games/content are using compressed HD audio (TrueHD+Atmos - this works just fine via eARC). The limitation is not in the hardware, because if you modify the AudioEDID of the LG HDMI-eARC port with an HDFury adapter the TV accepts the LPCM 8 channel audio and is passing the audio to the AVR, unmolested (as RTINGS did discover in their C9 review).

 

This is an essential feature, especially for such an expensive TV. Please boost this out and get LG's attention so they can fix this problem and make this an amazing TV.

 

Same issue with  C9 model was fixed.