Yeah I noticed this last night. It will play video just fine. Anything with DTS THD, Atmos yadda yadda yadda it will play the video but no audio, or in the odd case, simply not play anything at all.
I found that a little disappointing, but at least have an Nvidia Shield as backup and my Synology NAS to play those off of.
Have to say though, initial impressions of the player are that it is genuinely magnificent. I'm so glad I spent the extra money on an 820. Watched a bit of Apocalypse Now 4K Final Cut last night (I got the 6 disc set recently) and my word, it is glorious. The audio alone never mind the picture quality, is outstanding. With the HCX in use the picture looked stunning. I loved all the nerdy data too that you can bring up.
Probably the major plus point for me though is how it handles 24P content. Not a single frame of judder, jitter, stutter or other nonsense was witnessed. My telly and the player worked in tandem like a beautiful symphony. It was very erotic.
One last thing. I did try a couple of Region A discs too last night. I didn't even need to use the top menu trick, they just played. I found that odd. I'm going to try a few more and see how it goes. Hopefully I won't run in to major problems.
Overall though I'm absolutely delighted with the UB820. A lot of thanks is owed to the reviews and remarks I read across this forum over the past few weeks. I was going to just get something else, but in the end am very pleased I took a punt on a more expensive option, it's certainly been worth it so far.