Well, now fans think that GoT has either made a pretty huge mistake of its own - either that or they're hinting at something BIG that we've all missed for years.
As you would've noticed (but probably didn't pay much attention to) all the cast have their character's corresponding house sigil by their name in the show's opening credits.
Kit Harington (Jon Snow) has a wolf for House Stark, Lena Headey (Cersei Lannister) has a lion for House Lannister, and Emilia Clarke (Daenerys Targaryen) has a dragon for House Targaryen.
But weirdly a Reddit user noticed that Sophie Turner's name used to have a dragon next to it, instead of a wolf:
Though her sigil has since been changed to match the rest of her family, fans have been left wondering whether the biggest series in history could've made such a simple mistake, or whether the credits were a huge clue we all missed.