Other mistake: Near the end of the closing credits, when the Warner Bros. Copyright appears, you'll see the very first word "All" spelled incorrectly as "Al" in "All material is protected by Copyright Laws of the United States and other countries throughout the world." (01:26:40)
Other mistake: When Happy hits the ball in the alligators mouth, he is on the complete other side of the lake where the gator is located, and there is a crowd of people blocking his view, but somehow he can still see through the people and over the lake, to notice the gator taking his ball.
Other mistake: After Guy gets hurt in the warriors/ducks game, the scoreboard is shown. It says that there is 15 seconds left in the third period, when it is really the second period.
Other mistake: When Roy is about to hit the ball off the porta-potty, the TV commentator bets Romeo that he won't hit the shot onto the green. Roy's shot ends up on the fringe of the green, not on the putting surface itself (an important difference), but Dewey collects the bet.
Other mistake: At the start of the tournament, Big Earn steps beyond the foul line in his first frame.
Other mistake: Towards the beginning of the movie Dorothy first "meets" Jerry by eavesdropping on his conversation with a woman in the airplane. But Jerry is located in first class whereas Dorothy is in coach. Going by her seat location it seems like she's sitting at least 10 rows from Jerry, plus the area that divides coach from first class between them. And Jerry is speaking in a soft voice. Add to that the drone that an airplane makes (even if not airborne) and it's highly unlikely that she would have been able to hear him, even if he was the only person talking in the plane (also unlikely).