Apple would rather add more poop emojis than fix this issue! There's your emoji joke.
Is this issue exclusive to the 4k box or is it anything that supports Dolby Vision?
If the device supports DoVi, then it seems to revert to HDR10 (at least with the ATV box).
If the device doesn't support DoVi, then it reverts to SDR.
MacRumors failed to mention that in the article, making this look like an ATV issue only. Why report the whole thing when you can half-ass it.