When the Bash Street Kids meet the Keeper, the Teacher's shirt changes from brown to red.
When Scorcher burns a hole through Hank's store, the hole appears to be very big. But when Pa pulls out the chicken, the hole is much smaller.
When the Professor leaves Bash Street School, he walks past the Teacher, whose head appears to have disappeared for 2 frames.
In the monastery, the monks all appear to come out of the door which is closed.
When the Bash Steet Kids fall into Lake Beautiful, the Teacher says "Their faces. They're changing." His mouth is not open when he begins to say that line.