Continuity mistake: When Hawkeye and Eddie are dancing in the Swamp, after Hawkeye sits on the hot heater Eddie knocks over the tray of glasses and the mug, but next shot the mug is back up on the table.
Revealing mistake: While Hawkeye and Eddie are in the Swamp, when Eddie knocks over the stovepipe we can see that it's actually split into two pieces for the stunt, whereas in the previous shots it's not.
Love Story - S1-E14
Visible crew/equipment: After Radar tells Margaret that she's needed in the post-op ward Frank sneaks toward Margaret's tent, and when it cuts to Margaret walking into post-op, at the start of the shot we can see the two actors' curved chalk foot marks on the floor.
Love Story - S1-E14
Other mistake: After Hawkeye asks, "Radar who?" while he's kissing a nurse, it cuts to Trapper, Radar, and Hawkeye walking past a jeep parked in front of the mess tent, then another jeep shows up with Lieutenant Anderson, but both jeeps have the same stain (looks like rust) on the front bar - the same jeep was used in both shots.
Love Story - S1-E14
Continuity mistake: When Trapper puts on the "Dear John" recording, the record is moving at two different speeds in the close up and wide shots.
Character mistake: Hawkeye and Trapper make Tuttle an alumnus of "Berlin Polytechnic" and translate that (wrongly) as "Berlinishes Polytechnikum". Berlin's polytechnic university was named "Technische Hochschule Berlin" at the relevant time - and at no time offered a medical curriculum. To study medicine in Berlin, Tuttle would have to attend "Freie Universität Berlin" instead.
Suggested correction: And how are Hawkeye and Trapper suppose to know that? They are after all, making all this up. It is never meant to be factual.
It is intended to fool Margret and Frank, so it has to be assumed that they meant to pull it off. Hawkeye says "It can't be any place they'll check", which is why they select a German university in the first place. That shows it is indeed meant to be if not watertight, then at least convincing. To use an university you don't know the proper name of doesn't make sense under these circumstances.
Continuity mistake: After doing his pushups, Colonel Brighton puts on a red robe and talks with Trapper and Hawkeye. In some shots the cord from the robe's hood is hanging down and in others it is tucked in. (00:10:20)
Continuity mistake: When Frank is trying to examine the Colonel, in some shots Buzz's robe is open and in others it is tied at the waist. (00:10:50)
Continuity mistake: When Radar is slipping the glass of milk into Buzz's tent, we see the outside of the tent and there are no windows. From the inside, the milk is placed on a table that is right under a window. Also, the milk is already on the table in a scene before Radar puts it there. (00:13:20)
Revealing mistake: As Buzz is stopped at the tent door by Hawkeye and Trapper, the vertical edge of the "sky" is seen over the top of the hospital building, behind the camo net.
Sometimes You Hear the Bullet - S1-E17
Continuity mistake: Frank and Margaret are dancing in her tent when Frank's back seizes up; in the subsequent shots sometimes his arms are around her waist and sometimes around her shoulders. (00:02:30)
Sometimes You Hear the Bullet - S1-E17
Continuity mistake: Hawkeye lifts Wendell's arm, takes his pulse and lays his arm down by his side again. In the next shot, Wendell's arm is across his chest. (00:13:55)
Sometimes You Hear the Bullet - S1-E17
Continuity mistake: As Frank receives his purple heart, Henry calls him 'Franklin D. Burns' All other references to his full name in the series give his middle name as 'Marion'. (00:23:50)
Sometimes You Hear the Bullet - S1-E17
Other mistake: Wendel, afraid of being shipped home, is trying to escape from the MASH by hot-wiring a Jeep. Despite just having had an appendectomy, he is leaning forward and to the right from a sitting position, which would have to put pressure directly on the incision, yet when discovered by Hawkeye, he easily and without discomfort sits up straight. Aside from him still being at the MASH, we know the surgery is recent because, just a little later, he winces and complains after making a very small movement.
Sometimes You Hear the Bullet - S1-E17
Factual error: We see Pvt. Wendel trying to hot-wire a jeep to escape. He wouldn't have to hot-wire it, because vehicles assigned to a combat zone were equipped with an ignition switch, not an ignition lock, for the simple reason that keys get lost or mislaid all the time and in an emergency, having to track down keys for vehicles would be extremely detrimental to an unit's combat effectiveness.
Revealing mistake: When Hawkeye walks into the mess tent naked as per his bet with Trapper, in some shots, you can see that he is really still wearing shorts. (00:07:40)
Continuity mistake: In some shots, Radar's exam questions are in his hand, in others they are tucked under his arm. (00:10:30)