Does C4 track states? What I mean is does the "off" only work if someone chose a source to turn it on? This would explain why the OEM remote is required to turn it off. C4 still thinks it is off. An easy test would be (after the tv turns on by itself) to choose a source to turn it on...then turn the room off.

Try leaving the control cable (Ethernet) disconnected overnight. Does the TV turn on? If so connect the Ethernet cable and try leaving the hdmi cable disconnected overnight.