Other mistake: Laura tells Rob "oh you don't smoke!" But in several (double digit) episodes Rob not only has a lighter but also a cigarette in his hand or mouth. One episode while he and Laura are illegally about to eavesdrop he puts out the cigarette on the speaker causing the speaker to turn on and they start eavesdropping again.
The Dick Van Dyke Show (1961)
1 other mistake in The Meershatz Pipe - chronological order
Starring: Dick Van Dyke, Mary Tyler Moore, Morey Amsterdam, Larry Mathews, Rose Marie
Your Home Sweet Home is My Home Sweet Home - S4-E25
Continuity mistake: The Petrie house (where Rob and Laura, Jerry and Millie are standing together bickering) is completely different from the episode "Where Did I Come From?" and a few others.
Rob Petrie: At least I'll prove one thing tonight: Television writers marry the prettiest girls.
More trivia for The Dick Van Dyke Show