Continuity mistake: When the couple is in the boat when the creature appears, the woman is taking a picture and holding her phone in her left hand, she turns around and her left hand is raised and her right hand is on the boat edge. When the camera angle changes, her left hand is now on the boat and her right hand is lowered and holding the phone (confirmed when the camera angle changes again and she's in the same position, holding the phone in her right hand).
Grimm (2011)
1 continuity mistake in A Reptile Dysfunction
Starring: David Giuntoli, Russell Hornsby, Sasha Roiz, Silas Weir Mitchell, Bitsie Tulloch
Map of the Seven Knights - S5-E10
Factual error: The Czech crime database (which appears to be an official Czech database) is headed 'Czechoslovakia'. Czechoslovakia has not existed since the Czech Republic and Slovakia separated in 1993 and neither country uses the term any more.
Nick Burkhardt: I guess you don't have to be a hexenbiest to be a witch.
Adalind Schade: You don't have to be a witch to work this kind of magic.