Another similar thing made its way across the internets a few years ago: https://www.boredpanda.com/tv-put-subtitles-kids-channel-political-debate-sweden/

Back then I think the conclusion was that someone had set up teletext subtitles from the wrong channel on that TV. It wasn’t an error from the station. I could be remembering wrong though, since I can’t find a source for that.

On a side note: The language of the subtitles also seems weird if this happened in Iceland. Wouldn’t they be in Icelandic?