https://www.cnet.com/news/game-of-thrones-scene-truck-frozen-lake-hbo-photobomb/

Despite its big budget and sky-high production values, "Game of Thrones" does occasionally make minor mistakes, but leaving a modern pickup truck in the background of a scene isn't one of them. 

A viral screenshot crashed its way across the internet from Twitter to Reddit this week. On the surface, it looks pretty convincing. It's a scene from Sunday's frozen-lake battle showing a wight horde, our heroes on an island and a white pickup truck in the distance behind all the action. Yes, this actually happened. No, it wasn't in the episode broadcast on Sunday.