In the previous episode, it was stated that Yolanda's school-wide humiliation took place three months prior. However, if the timing of these episodes is in October (as this episode takes place on Halloween), then three months earlier would be July, when the normal school year isn't likely to be in session.
In the theatre, Sharpe flips the Empire technician a chocolate covered coin. The sound dubbed in is of a real (metallic) coin being flipped. The "foil" on a chocolate covered coin cannot make a metallic sound when flipped.
Pat's car won't start. Rick Tyler, walking past, says, "Sounds like the alternator". That can't be right: the battery provides the energy to start the engine; the alternator is only operative while the engine is running. It charges the battery and provides electricity for accessories, but it has no function in starting the engine.
Near the beginning of the first present day scene, when Matt and Rick are standing off against each other, stood face to face, after Matt invites Rick to take a swing, Matt's mouth moves as he says something else, but nothing is heard. The audio has clearly been altered without bothering to edit or re-shoot the visual.