* The porch has 2 columns right across from the front door, but when Stan is talking to the carolers, the columns are missing.
* When Stan buys the Disco cassette, there is a green design on the back, but when Roger finds it in 1970, the green design has vanished.
* John Hinckley, Jr. leaves his popcorn on the seat when he leaves the theater, but when Michelle talks about how she can't go back to the tooth fairy guild, the popcorn has vanished.