That is important to know for sony TV (tested with KD-55XG9505 and X950G but should affect nearly all Sony tv): 
If we have DD+ selected in ARC mode, we can play netflix and the stream is DD. When we switch to other input on TV (we have shield connected playing youtube) the ARC remains correctly but audio is mute from youtube. 
However, when we click remote controller we can hear the "clicks" correctly so the audio system is actually working but TV ignores the music stream. This does not happen if we have DD selected from TV global settings. This is a TV issue.

Another TV issue we noticed is if we use the hotkey NETFLIX on remote that goes directly to netflix we lose sound. However, if we go there using the home button and then select netflix we don't lose audio..

We have confirmed in PCM mode TV always sends out multichannel LPCM 8 channel information with stereo speaker allocation info (incorrect data). This means only stereo works and no multichannel LPCM actually comes out of TV. 
Similar issue than with LG C9.