Goodbye, Farewell, and Amen - S11-E16
Continuity mistake: When Hawkeye is returning to camp, he and his driver completely pass some Burma-Shave signs the other have set up to welcome him back. An ambulance bus is a few feet behind them and manages to then suddenly appear at least 30 feet behind them to smash all the signs.
Suggested correction: That could very easily be the result of someone's wish.