Continuity mistake: When BJ arrives in Korea, he, Hawkeye and Radar are attacked by guerillas while changing a flat tire on their jeep. After installing the spare tire from the back of the jeep, Hawkeye rolls the flat tire off the to the side of the road and jumps into the jeep as Radar speeds off. Later, when they reach the camp, the spare tire has reappeared on the back of the jeep.
Character mistake: When Hawkeye asks Frank what he is doing, Frank replies he is lining up all bottles and jars "according to height and popularity". In fact, the bottles are not lined up according to height at all, also the order of condiments is different on the two tables. The sweet and sour gherkins Frank mentions are not there at all - during the pan shots you can see the line ends with the pepper.
Factual error: Klinger says he would wear Hula Hoops(R) in his ears if it would get him a discharge. For several reasons, he is using a phrase that does not yet exist: 1) Show wise, Klinger will later try to convince Charles to invest in developing a new toy, a hoola hoop like plastic tube, being inspired by Korean children playing, and 2) plastic hoops which came to be called Hula Hoops were only introduced by Whamo in 1958. Setting episode dates is always difficult for MASH, but the Mash Olympics (inspired by the 52 Helsinki games) are still to come so we can say it must be 52. 3) The Hula Hoop trademark was only registered in 1962 to Whamo. No info. as to what name the hoops were marketed under prior to 62, but Klinger is using a term at probably ten years, at least 6 years, before it came into use.
Continuity mistake: B.J. is holding a Korean child who is subbing in for his own daughter when Margaret hands B.J. a piece of cake. Just as it looks as if he is about to feed the cake to the girl, the scene cuts to a full facial shot of Hot Lips, then cuts back to B.J. The cake has disappeared. There wasn't enough time to eat it all, and neither the child nor B.J. is eating. B.J. has no icing on his fingers; it has just disappeared.
Factual error: Charles mistakenly injects a post op patient with curare instead of morphine. This would have been hard to do. Curare was not approved for use in Korea by the U.S. Army and it would not have been there. Even if it had been, curare was used in conjunction with anesthetics in the operating theatre. It would make no sense to have it in the post op. (source pg. 14 "Notable Names in Anasthesia" by J. Roger Maltby, Royal Society of Medicine - Great Britain).
Continuity mistake: When Radar calls assembly, the very first shot shows some troops appearing on the parade ground. Klinger, in his straw hat, appears on parade in the front rank in the top right hand corner of the screen and stands to attention. In the next shot, however, he is seen approaching the parade ground at the double from the Post Op ward building. Next shot, he is on parade, but in the centre of the rear rank. A couple of shots later, when Major Burns addresses the troops, he is back in the front rank - screen top right. This position is confirmed later when Burns addresses him by turning his head sharp left (he is facing the parade), and Hoolihan is seen marching over to him to remove his hat.
Factual error: When BJ and Hawkeye go to Potter to talk about Cho Lin wanting to get married at the 4077th, Potter mentions he expects to be home in Nebraska in 16 months, three weeks and four days when they try to fool Potter about Cho Lin. Potter has always said he and his family live in Missouri, however.