When Ethan presses the medal against Miss Ives' forehead, the chain falls to the left side of her face. It changes to the right side on the close up, and goes back to the left in the wide shot.
Vanessa gets her Latin grammar wrong, saying "terra incognito", when it should be "terra incognita". It's unlikely an educated person in the 19th century would make this mistake.
Dr Frankenstein says he is going to give Vanessa vitamins. The word wasn't coined until 1912.
At the 39 minute mark of S2 E7, Reeve Carney (Dorian Grey) is seeing Lily Frankenstein off but calls her Billie instead of Lily.