Mr. Monk is the Best Man - S8-E13
Character mistake: At the end, after Stephanie fired the gun, Captain Stottlemeyer shows her the gun's magazine but calls it a "clip." A police captain like Leland would know the difference between a clip and a magazine and would use the right word.
Mr. Monk and the Badge - S8-E14
Character mistake: When Monk is talking to the cops on the shooting range about the window washer's story, he says that the window washer said he was on the 7th story of the building. But in the press conference Monk saw in the bar, he said he was on the 6th story. Monk isn't likely to forget a detail like that, especially since it's the detail that's bothering him about the story. (00:19:25)
Mr. Monk Goes Camping - S8-E12
Character mistake: The campers suspend their packs with food from a tree, while the two criminals watch from behind a tree. Criminal 1 asks, "What are they doing?" Criminal 2 responds, "They're getting their food off the ground, it keeps the bears away." But they only suspend the packs a few feet off the ground, still easily within reach of the criminals and certainly within reach of a bear.
Happy Birthday, Mr. Monk - S8-E9
Character mistake: Given how Monk is it seems unlikely he'd forget about being in a dumpster filled with garbage and be able to enjoy a birthday party, even if it's his own.
Answer: Notice also that in the opening credits scene when he is touching parking meters her also wipes his hand on his clothes each time he does it.