Twice the Grieving, Double the Loss - S1-E7
Revealing mistake: When Jake screams "Talk to me!" at the doll in the station and it says "Hi, I'm Billy! Wanna play?!", you can tell the reflection of Jake in the plastic has been added in post. It unnaturally wobbles a little bit at the end of the shot, especially his shoulder area. (Looks like they tried to motion-stabilize the shot used for the reflection a bit, which can sometimes make a weird "wobble.")