Why is it that, when I activate the “Giveaway” screen, I hear someone else’d stream???
What do you mean? Can you provide a video explaining the behavior you’re seeing?
It’s also happening to me, it is exactly as he describes it:
Whenever we open: “Giveaway” some random channel (one of the ones on the Twitch startpage / homepage, I checked it) starts running in the background, it has been happening to me too and it is not fun to tell the viewers each time: “Sorry guys, I don’t know what is happening either and I have tried to see if I could fix it, but doesn’t seem like I can do anything about it at the moment.”
This is probably a bug in Twitch’s chat embed then, which is unfortunately not something we can fix. I would recommend reporting this as a bug to Twitch.