Other mistake: During Lady's first night home, there's a shot of the family's clock: the number seven is painted as a six.
Lady and the Tramp (1955)
1 other mistake - chronological order
Directed by: Wilfred Jackson, Clyde Geronimi, Hamilton Luske
Starring: Bill Thompson, Verna Felton, Barbara Luddy, Bill Baucom, Larry Roberts, Peggy Lee
Continuity mistake: When Jock and Trusty are telling Lady that Darling is having a baby, Lady's collar changes from blue to brown and back to blue when Tramp comes close to her.
Boris: Ah, but remember, my friends. Even Tramp has his Achilles heel.
Pedro: Pardon me, amigo. What is this chili deal?
Boris: Achilles heel, Pedro. This is meaning his, uh, weaknesses.
Toughy: Oh! Oh, the dames. Yeah.
Bulldog in Pound: He has an eye for a well-turned paw, he has. Let's see, there's been Lulu.
Toughy: Yeah, and Trixie.
Dachsie: Und Fifi.
Pedro: And my sister, Rosita Chiquita Juanita Chihuahua. I think.
Trivia: One of the filmmakers suggested introducing a newborn baby in the story because he had just had a baby, and thought it was interesting to watch his own dog react to a new baby in the house.