The Crab with the Golden Claws: Part 1 - S1-E1
Continuity mistake: When Tintin borrows the torn out part of the wrapper, he and Snowy go to leave the office and the shot cuts back to Thompson and Thomson. For the very first frame of the shot, the top of the pile shows two blue files and on the bottom is two darker blue files. The bottom two files are shown with dark blue edges. Then within that same shot, a frame after, it is now a blue file at the top of the pile and a red file below the blue file and the edges from the dark blue files have vanished. (00:03:50)