When Parker is starting to dish out some of the honey orange sauce for himself there is a stain on the table cloth in front of him. Then from a side shot when dessert is being served the stain is missing.
The Captain and Carpenter leave McHale's Island in a rubber raft going back to their base but both end up totally submerged In the water. Later when he is shown talking to the doctor, his uniform is only wet in spots on his right side.
The end of the exercise belt McHale uses is attached to the rim of the jeep wheel supposedly to jiggle the belt as the wheel turns but if it were attached to the rim as shown the end of the belt would rotate as much as the wheel not just jiggle in place.