When the guests sit down to dinner, there are places for everyone. Since Mrs. Van Twitchell was expecting only one escort, there should have been two seats too few.
When the Stooges arrive at Mrs. Van Twitchell's home and she tells Clayhammer that they are expected, Clayhammer says, "Very well, Mrs. Van Twitchett".
As Bud Jamison's British character looks through the drilled hole in the wall, the wall is already wet before he's sprayed by Curly.
When Bess Flowers goes under the staircase room to make a phone call it is clear that she has plenty of head room while standing. But when Curley drills a hole into the room, Bess Flowers suddenly pops up with her head through the staircase steps. Now standing 2 feet taller than Larry and Curley. Obvious mistake by production crew.