The Curious Tale of Mr Spearfish - S3-E1
Character mistake: The whole mystery kicks off when Creek sees a photograph of Alice Spearfish with her parents, and concludes that she is adopted because two people with brown eyes cannot have a child with blue eyes. An obsessive polymath like Creek must surely know that that is wrong. The genetics are complex and though uncommon it is possible for a couple with brown eyes to have a child with blue eyes and the other way around.
The Curious Tale of Mr Spearfish - S3-E1
Continuity mistake: The bullet marks on Lenny keep changing places.
Factual error: When it's is revealed that The Omega Man is made of mercury, it is explained that it needs to be frozen to a temp of -38.87c, then it's shown being taken out of the freezer and the mold being removed with bare hands, which would be impossible at that temperature.
Suggested correction: Jonathan actually states it's a photo of 2 blue eyed parents and a brown eyed daughter.
Which is still possible! It isn't even uncommon. Brown eyed parents can have a blue eyed child and vice versa - that's what recessive genes are all about.