Annoying DTS issue, any ideas?

I’m running my raspberry pi 3 with Milhouse’s nightly Libreelec Kodi build. I couldn’t be happier with it and it is a rock solid software solution. However, I do have one niggle.

My HDMI goes from the PI3 to my LG TV which then comes out the TV to my Yamaha receiver. This works fine using the “pass-through” settings in Kodi and my receiver recognizes and decodes 5.1 Dolby perfectly.

However, if I have a video with a DTS audio track it does not even recognize it on the receiver and instead plays the background audio only (presumably using PCM).

I’m guessing CEC from the TV is telling Kodi it can’t pass it through and because of this the PI3 is attempting to decode DTS on the fly and failing miserably.

If that is the case, could this be a CEC issue and just disabling CEC may be a solution? (if so, how?)

Or am I better off just getting an HDMI / TOSLINK splitter and going directly to the receiver instead?

Or failing that, just investing in a better hardware solution with built in TOSLINK?

Any help would be much appreciated!