I have an issue where I can only play HDR files when Adjust Refresh Rate is disabled. If I enable this setting, HDR files simply show a black screen and eventually the TV tells me there is no signal. The HDR logo comes on at the top right.
TV is an LG model from 2018. No issues playing other types of files, or playing HDR streams from Netflix/Amazon etc.
Debug log is here http://paste.osmc.io/yizufuwiza.vhdl
I tested with 3 files, the first being an HDR source, then a normal 4k source, then back to the HDR source again.