After Klinger says, "Sandwiches from the mess tent," the position and quantity of the sandwiches are different in the next shot.
When the poker game commences at 6:00 PM (1800 hours), it is dark outside. But at Uijeongbu's latitude, sunset occurs at or around 6 PM only from October 11 to February 6 (and the sun would have had to have set significantly earlier than 6:00 for it to have been completely dark outside). However, judging from how everyone is dressed during the episode, the temperature is far too mild for the time of year to have been between October and February.
Trapper says that Frank has "put him off on reenlisting." But Trapper is an officer, and officers do not enlist or reenlist. Only the enlisted (NCOs and Privates) can reenlist.
"Whiplash Hwang" is raised considerably higher in his bed in the shot from behind him than the shot in front of him.
The wounded soldier in OR is apparently Army Counter Intelligence but Frank keeps referring to him as "C.I.D.". "C.I.D." is Criminal Investigation Division. Counter Intelligence would be referred to as "C.I.C." (Counter Intelligence Corps)