Sorry to revive an old thread but I've been having this issue. I will try this solution of using non ARC hdmi slot.
However, a major point and benefit in an AV setup, is using ARC and also having all sources without switching hdmi sources on the TV.
As it's nearly a year now, I was wo seeing if there is another solution to this?
Fyi, my V6 box is connected to my av receiver (yamaha rxv585) and another hdmi back to the ARC input on my TV. All cables are hdmi 2.0 (V6 box uses the cable that came with it which I assume is 2.0 as it's a 4k box)
As for HDMI ARC: TVs are for viewing and are not designed to process audio from an HDMI source, so they do it with varying degrees of competence. For example, it's not at all uncommon for some people to find that their TV converts 5.1 audio to stereo. Furthermore ARC has restricted bandwidth as it's a replacement for S/PDIF and also has S/PDIF's restrictions such as the inability to support advanced audio file formats like Dolby TrueHD, DTS-HD and Dolby Atmos. I expect these problems to be resolved when eARC becomes widely deployed, but in the meantime it's best if you have a sound system into which your sources such as a V6 are plugged into and the TV connected to the sound system by an HDMI cable.