EDIT : going to post this in debug
Green HDR image on AMD RX550
Libreelec 12 latest nightly-generic on AMD RX550 2GB via hdmi 2.0. Cables and tv work with HDR no problem on another Libreelec box with AMD APU, also LE nightly-generic.
Logfile : first I play a HDR10 file with green image as below. Then I play a testfile from Kodi-samples with HDR10 bt2020, colors are okay but no hdr.
One quirk that messed stuff up for me was powering on my receiver (for surround sound) while tv was showing LE. Cec would freak out. So now I first switch to another source on the tv, then turn the receiver on, wait till tv says audio has switched, and then I go back to LE.
Search for the thread explaining how to link the command "systemctl stop kodi" to a menu-item or button on your remote. It was I remember with linking a script .sh to something to what you need.
I did a lot of testing...
My tv is doing things right. The magic bad word appears to be LSPCON. I was happy to see the HP Elitedesk 800 G3 sff support an i3-7100 and even hdmi 2.0 (with a cheap addon option board thx AliExpress). But the board uses an LSPCON-chip and sources it's video from the DisplayPort 1.2. That is according to this forum no bueno.
chewitt Thank for your help.
I'm atm not yet able to reply fully, but I have tested with blank guisettings.old and also blank .kodi. It's really intermittend what I'm experiencing but the problems persist.
I now have another computer with Athlon 3000G to test with and will finally be able to tell if it's the tv or LE.
I'll keep you posted.
(other fps also)
I'm using LE12 nightly generic 20231206 on Intel HD630. HDR is working on my Sony. Here is my edid. Overscan is disabled on the tv.
in 1080p en 2160p "everything" 24fps gets zoomed to 4800x2596. I was only once able to move the blue bottom-right edge in calibration, but now nothing moves anymore. The player used to zoom to +5000x.... before I managed that one time to adjust to something smaller.
There is an interaction with this behaviour and Settings/Player/Videos/Adjust display HDR mode (my tv does HDR10 and HLG).
With "Adjust display HDR mode" checked you get the mega-zoom like in this post.
With "Adjust display HDR mode" unchecked you get a misalligned sync (instead of zoom-error). See images in my previous post.
Was it something I did ? 
I want to use nano while in ssh. I'm on LE12 generic nightly.
# nano
Error opening terminal: xterm-256colorI followed this but TERM remains unchanged. Also tried TERM=screen but same.
in .profile this line :
export TERM=screenI found a fix. My whitelist was empty when I posted the first time and so I got a lot of these weird screen misallignments. Then I threw every resolution my Sony could handle in the whitelist. I still had weirdness but LESS...
So the fix was to leave everything in the whitelist except for resolutions with 24 and 23,98 fps. Kodi now transforms a source with 24 and 23,98 to for example 25 or 60 fps which play fine.
I always used a Nvidia Shield before so the past few days I had to find my way with x86. I now sometimes have for example active deinterlacing active while playing, that's a blast from the past.
(Posting here because of mentions of refresh rate).
I'm using LE 12 nightly generic 20231206 on Intel HD630. HDR is working on my Sony.
I have an intermittent sync problem for pretty much every refresh rate/resolution combo. I think start of sync doesn't get reset to topleft when refresh rate changes. Not only when playing but also regular UI.
Is this a known issue?