I have an LG 32LD420 TV and an RPI4 4Gb
With libreelec 9, I had no problems
Then I switched to libreelec 10
The tv turned on automatically after 10 to 15 seconds.
I found the solution by installing version 10.0.2 then reinstalling over version 10.0.0 and there it worked
Since version 11.0.0 and 11.0.1, the TV turns on again after about ten seconds
Even trying different CEC settings (proposed in forums), it doesn't work
So since then, I've been using Kodi on a XIAOMI Mi TV Stick to connect to my raspberry and be able to turn off my TV without it turning on again.
Is my TV too old to work with today's CEC standards?