Birthright - S6-E1
Continuity mistake: Abigail Breslin's front teeth change length throughout the episode.
Birthright - S6-E1
Revealing mistake: When Munch is driving after the perpetrator you can see the dent in the side of the car moments before he actually hits the car and goes over the bonnet.
Other mistake: When Fin is looking at the drivers licenses of Vance and Trish, both as listed as female with identical birth dates.
Answer: It was a misconception about Jehovah's Witnesses beliefs. Only blood transfusions are discouraged in their beliefs, medically.