As BJ and Hawkeye are sampling the Spam Parmesan, the shot changes and there is suddenly much less food on the plate.
When Father Mulcahy, Margaret, BJ and Hawkeye are talking to Col. Potter in the mess tent, Loretta Swit's fingernails can be seen to be almost an inch long. No nurse, especially a head nurse, would have fingernails that long.
When Conway meets Gen. Haggerty, he salutes the general indoors. This is not proper military protocol. When indoors, a subordinate comes to attention, but does not salute.