Hi,
I have the same issue with 100% issues and moreover when I start to play as well.
New install, Denon AVR-2313, TV LG 55UF860V and RPi2/LibreElec or Odroid-N2/CoreElec.
Working perfectly with Rpi2/LibreElec @1080 but issue with Odroid-N2/CoreElec @2160.
I noticed that @1080 the time between STOP key press and CoreElec menu is around 2-3 seconds, bigger than RPi2.
In this post MeisterP said the issue is at the AVR side.
I agree with phaze75, the issue status should NOT be solved.
Do anybody have a fix now?