I have a generic Android box feeding a Panasonic TV in the bedroom. I use the @Apsattv playlist with Kodi to watch different channels. I don't normally watch APNA TV but in the past it displayed normally, like every other channel. Just now I happened to click on it and got something very different. I can see the regular picture in the background, but most of the screen is covered with vivid flashing blocks of green, ideally suited to triggering epileptic seizures in anyone prone to such things. I don't have this effect on any other channel. Can anyone tell me what is causing this? Does it have to do with 4K? My TV is only capable of ordinary HD. 

I am not bothered by this since I don't watch APNA, just curious what is causing it.