The Crab with the Golden Claws: Part 2 - S1-E2
Other mistake: The newspaper article that features Tintin and Captain Haddock at the end of the episode is a flipped shot, as shown by the text that has been reversed. (00:43:35)
Continuity mistake: When Marshall first finds Trip's letter, he holds it from the left side. In the close-up, he's holding it from the right side. (00:02:10)