While Klinger is changing a light bulb in Colonel Potter's office, he is wearing white gloves. When the camera cuts to another angle, he is gloveless.
At the end, BJ plugs in Frank's radio and it starts playing immediately. A radio of that vintage would have vacuum tubes and would require a 20 second warm up after being powered up to play music.
However, being familiar with the set's average warm-up delay and how long Hawkeye's 'ritual' would last, BJ could have applied power some time before to achieve the appropriate effect.
Potter pays the Korean vendor in US currency, which he would not have. US military personnel were paid in military script.
The injured Korean's dried blood stain is bright red. Dried blood usually more brownish.
The Korean spirit post, erected by locals, has either Chinese or Japanese writing on it, which wouldn't have been the case. Most locals in Korea during that time would not know how to write either language.
When Radar first moves the spirit post at Colonel Potter's order, he carries it several feet with obvious effort. But when he sets it down, it wobbles noticeably, revealing that it's actually a very light prop.
The spirit post that the local Koreans put up to drive away evil spirits is inscribed with Chinese characters, not Korean.
It is unclear why the spirit post couldn't simply be moved a few feet to a place where it didn't block traffic.
The Exorcist could exorcise the demons from the old man, there was no need for him to jump in front of a car.
When the person on the bike crashes into the cart after radar has taken the post away the boom mic shadow can be seen on the ground.
In the first OR scene, BJ asks the nurse for a knife as he prepares to operate. Being a surgeon, he should have asked for a scalpel.