Hawkeye tells Winchester that his mother died when he was young. But the pilot episode in Season 1 establishes that both of his parents are alive when the 4077th sends the boy Ho-Jon to live with them.
While Hawkeye is waiting for his call to Maine, he tells Charles about the time his mother died when he was 10. However, in #1.18 ("Dear Dad, Again"), Hawkeye closes his letter to his father with "Kiss mom and sis."
Hawkeye and Winchester stay by the phone all night waiting for a call. This is also the room that Klinger sleeps in, but we never see him.
When Goldman is constructing the bowling lane in the mess tent, Col. Potter orders him to put 12 coats of wax on it before morning. It is still daytime. But later that night, Father Mulcahy and B.J. are shown practicing, and the lane clearly has been waxed. It would be a stretch for 12 coats to be applied by the morning after Col. Potter ordered it, considering that each coat would have to be applied evenly and allowed to dry before the next coat could be laid down. But if the lane already is being used, the 12 coats must have been applied before they all went to bed, which means that 12 coats were applied in a matter of hours rather than overnight -- which would be impossible.
In the final bowling scene by Major Houlihan you can see an extra bowling pin being thrown in from the left side of the screen.