[billbillw]

So, to update on this for any Kaby Lake NUC users, I figured out that it was something to do with my Yamaha receiver. I recently swapped receivers to an Integra (Onkyo) DTR-50.5 and the DTS-HD/TrueHD are passing perfectly using LibreElec. I actually tried the Official 8.90.x alpha and it is working fine under both 24p and 60p. So, nobody ever responded with an thoughts from my Log (above), so I will probably never know if it was a bad Yamaha receiver, or just something between Yamaha and LibreElec/Kodi that was preventing the HD audio from passing.

Just keep this in mind if you are having HD audio problems and have a Yamaha receiver.

I'm fairly sure that Yamaha has been identified as a brand that has caused problems with Kodi audio in the past, along with Denon/Marantz. I don't know if this is a Kodi, kernel or even Intel hardware issue, or just a bug in the AVR firmware, but generally speaking almost all other AVR brands are working fine with HD audio (which is probably why nobody responded, as the problem isn't on the LibreELEC end of the HDMI cable).

@fritsch can probably speak more about the problems he's experienced with Denon/Marantz, while I've never had a problem with Onkyo. I'm sure you'll be very happy with your Integra now that you've finally got working HD audio!  

 Yes, although I was not happy that the Yamaha died suddenly without warning, I am very pleased to be using LibreElec again. Windows was a frustration almost every time I turned it on.