Factual error: Radar claims in his report that Father Mulchahy tried to calm the prisoner by saying "bang zhao", thinking it means "peace and friendship" when it really means "your daughter's pregnancy brings much joy to our village." There is, unsurprisingly, not even a remotely similar word in Chinese that means either of those things.
Factual error: In this episode, Henry is seen handing Radar the keys to his jeep. While this probably benefited the understanding of the audience, it is historically incorrect. Jeeps assigned to a combat zone were outfitted with an ignition switch, not an ignition lock, for the simple reason that in an emergency the vehicle had to be useable by anyone. (00:03:40)
Factual error: In surgery Trapper John is singing Frank Sinatra's version of "I got you under my skin". Although it was written in 1936, Sinatra did not release it until 1956, after the Korean War ended. The 1936 version sung by Al Bowlly sounds nothing like the version Trapper John was singing, which was mimicking Sinatra's version.