Withdrawal - S2-E1
Revealing mistake: At 46:24, Peter and Mozzie are sat on a bench. Peter's paper has the exact same wording on back pages as well as the front page. (00:46:24)
Revealing mistake: When Soliday becomes possessed and grabs the steering wheel of the car, you can see the small explosion effect that causes the car to flip.
The Royal We - S3-E2
Revealing mistake: On the RV of the guy being accused of molesting the girls, someone has written "PERVERT" in red spray paint. At a point you see Lightman next to a car, and the RV in the background, and the text is mirrored reading: "TREVREP", showing that during editing, this shot was flipped. (00:15:30)