When Jake is struggling to tie his bow-tie, he asks George for help, but George doesn't hear him while talking on the phone. In the next scene, the bow-tie is perfectly tied.
When Betty comes into the Bell Book and Candle and Cassie is waving incense around, she says it is because people are extra stresses at that time of year and its soothing, but the incense isn't actually lit. Except that when she puts the incense stick in its holder, the ash tip can be clearly seen.
The closing credits incorrectly say that James McGowan played Leon Deeks. The actor who played him was in fact Graham Abbey (who starred alongside McGowan in The Border (2008)).