The Broken Ear: Part 2 - S2-E3
Deliberate mistake: When the villains' cuffs are unlocked, only one of the locks get unlocked, yet the cuffs come off both hands. (00:25:10)
Deliberate mistake: Captain Haddock finds out the SOS was a fake so he tells the engine room to increase speed. Just after they increase speed and Tintin says "The people financing the Peary", we can tell the boat isn't moving since the background is entirely still and not moving an inch. (00:14:45)
Chosen answer: It is a pill that makes alcohol taste disgusting.