Other mistake: The calendar on the wall in Porky's kitchen shows April as having 31 days instead of 30.
Other mistake: Just one second after Bugs puts a letter (presumably an order for a pair of earmuffs) into a mailbox, a courier arrives with a package containing the earmuffs.
Other mistake: Just as Ichabod Crane places his coat across a small stream of muddy water so Katrina can cross, Brom Bones rides his horse through the water, creating a large splash. Ichabod winds up covered with mud and sitting in the water. Brom scoops up Katrina and rides off with her. There is not a speck of mud or water on her, on Brom or on the horse.