Be aware that SPOILERS are ahead for Fantastic Beasts: The Crimes of Grindelwald. Continue at your own peril.
Harry Potter fans experienced a confusing moment while watching Fantastic Beasts: The Crimes of Grindelwald during opening weekend, which included the brief return of a Hogwarts professor that held a prominent role in the Harry Potter series – Minerva McGonagall.
Fans became upset due to the inaccurate age of Professor McGonagall, according to the extensive Harry Potter timeline – written by J.K. Rowling herself – that reports McGonagall was born on Oct. 4 in the year 1935. With The Crimes of Grindelwald taking place in 1927, technically that would make her minus 8-years-old.
Source: IGN.com Fantastic Beasts: Breaking Down Professor McGonagall's Cameo