I first reported here, but noticed this morning that thread is very old (the forum is not using my locale date format):
I've been running 4 x old super stable OpenELEC 5.0.8 Kodi 14.2 on on Intel NUC D34010WYK Core i3.
Connected to Marantz AVR via HDMI, connected to LG TV.
Configured for HDMI audio passthrough, and refresh rate switching on start/stop.
I've been running this old stable build for a long time, no complaints from kids or wife.
I wanted to try the new Plex plugin, and I switched to the latest released LibreELEC-Generic.x86_64-7.0.2.img.gz.
On 24fps videos, when I start playing, the screen will go black with no audio.
Pressing the stop or back remote buttons sometimes returns to the main screen, if not, I have to reboot using SSH or the iOS remote app.
If I disable refresh rate switching, the video plays at 1080p 60fps, and no black screen.
At first I thought this was a Plex plugin problem, but last night I noticed the issue when playing directly from Kodi:
Blacks screen on play when refreshrate switching is enabled · Issue #56 · plexinc/plex-for-kodi · GitHub
I installed the latest LibreELEC-Generic.x86_64-7.90.010.img.gz, and the same still happens.
Attached is a debug log when playing from Plex.
Today I will try the just released OpenELEC 7.0.0 and see if it also has this problem.