So Here the situation for me as of now (todays nightly LE12):
nuc11i3 -> denon 1703-->panasonic 65HZ2000
- audio is stable as long as no pass through is attempted (note the TV can already do all formats)
- passthru works for non hd formats
- passthru doesn't passthrough any hd
-- dts ma becomes dts-- trying trueHD (7.1 in my case) kills all audio, and the system needs to be restarted to regain any audio
- UHD (4k) - tv via tvh-client doesn't play with HEVC VAAPi. Sometimes even not with VAAPI disabled, could not determine yet why.
There may be other things, but these are the issues I have, that used to work in LE 9 (or was it 10 , I forgot)