Nearly 10 years after Kodi 17 Audio Engine introduced this bug the AVDVPlus R10 build released yesterday properly fixed it with HDDVD DD+ bit-streaming properly for all AVRs (Including Universal HDDVD rips).
For those of you with a suitable AMLogic box, the new build is here:
https://github.com/avdvplus/Builds/releases
Hopefully the fixes will be backported to mainline Kodi.