So I mentioned this before earlier in this thread, I have three Apple TV 4K's two first GEN and 1 3rd GEN. Today I took the third GEN from the basement theater room and took it upstairs to the family room and swapped out the first GEN in use up there. 5.1 did not work in auto mode but as soon as I did the change thing in settings and selected 5.1... bingo ! worked fine old recover shows 3.2/1 on the display, so certainly in my case it is clearly not affecting the third GEN 4K devices. It may be different for some other people's devices who knows but it's clearly verified here that it is only the first GEN devices that have that issue.