Technical issues with Heroes III.

Might be off-topic, but I noticed a very interesting bug/fact with Heroes of Might and Magic III. I don't even know what to call it, but the gist is this: There's a TV in the room, with a decimeter antenna next to it. It receives a digital signal in DVB-T2 format. Under the TV is a computer. They are not connected in any way except for the common power outlet. I'm browsing the internet - the TV is showing. I launch any programs or games - the TV is still showing. But as soon as I load "Heroes III: The Shadow of Death," the signal to the TV is immediately cut off. I press the exit button, and the signal to the TV returns. How is this even possible??? There are no Wi-Fi or other radio transmitters.