this issue seems to only manifest itself on some TVs and only at 1080p, if I switch to any other resolution I can change this settings, no idea what AMD have done here.
please can the AMD devs be asked to have a look at what has changed between driver versions to see if there is something in particular 1080p is doing where its getting totally locked to 4:4:4 YBCR 12 bit.
My TV is LG EFO950v 2015 OLED