1. Try other HDMI ports.
2. Disable HDMI CeC.
3. Tell the seller and maker that it must be fixed or back it goes.
For me, I didn't find Android OS to be needed on the TV to use Android boxes. There was some that thought that was a requirement.
I bought a Sony Bravia XBR-700D a week ago, everything is working fine except the sound on my stb emulator.
When I launch or switch a channel on the emulator my tv volume increase to it maximum. I do not have the same problem when I am watching a program in kodi or on the tv itself.
My tv is directly connected to internet via wireless, no extra device at all, the sound come from the tv, no hdmi or av cable. The Android version of the tv is 6.0.1.
Any help will be appreciated, it is a good tv and I do not want to take it back to the vendor just for that.
By the way is there any other smart tv make with Android OS on it other than Sony.