Other mistake: The Rev. W. Awdry is not credited in the title card of the episodes "Mike's Whistle", "Tit for Tat", and "Useful Railway." Only Andrew Brenner's name appears.
Thomas the Tank Engine & Friends (1984)
1 mistake in Season 20 generally - chronological order
Starring: Alec Baldwin, Michael Brandon, Ben Small, Martin Sherman, Michael Angelis
Duke: Excuse me. Are you a vandal? Driver told me vandals smash and break things.
Thomas' Christmas Party - S1-E26
Trivia: At the end, the podium on which The Fat Controller is standing, is made of LEGO bricks.
Question: Why was Henry put on a barge instead of being taken to the works?
Answer: He was in the water.