I have a weird problem that started a while back ago. I didn’t have this problem at first, after installing it on the Pi2. It probably happened after an upgrade.
I have my Pi2 with OSMC connected to an Onkyo receiver via HDMI, and that receiver is connected to a Samsung TV, also via HDMI.
If I turn the TV off with OSMC selected as a source, the receiver turns off, as expected, but 5 seconds later the receiver and TV turns back on. If I choose the bluray player or Chromecast as a source, then they stay off as expected.
If I manually select the Chromecast as a source, OSMC will “fight” to get back as the selected source, so I must select the Chromecast repeatedly until OSMC “gives up”.
So it seems like OSMC sends a hdmi-cec “wake up” signal every time something happens.
I have tried setting hdmi_ignore_cec_init=1 in /boot/config.txt and in the settings for “CEC Adapter” I have disabled everything apart from “enabled” (I rely on using the tv remote for navigation, so turning HDMI-CEC off is not an option.)