What Does Blue Want to Build? - S2-E2
Revealing mistake: When Mailbox first comes in, you can see the letter being moved into place behind Mailbox due to a small part of him being cut off. (00:13:00)
Blue's Clues (1996)
1 revealing mistake in What Does Blue Want to Build? - chronological order
Starring: Aleisha Allen, Steve Burns, Seth O'Hickory, Traci Paige Johnson
Continuity mistake: When Steve sings the Blue's Clues theme, he is wearing tan shoes he wore in few other episodes. When he drops his notebook after the theme, he is back in his brown shoes.
What Story Does Blue Want to Play? - S1-E16
Trivia: At the end when Steve sings the So Long song, he's impersonating Elvis Presley.