Mr. Monk Is Underwater - S7-E5
Character mistake: Commander Whitaker asks what Monk and Natalie are doing on his "ship." No submarine commander would ever refer to his vessel that way. He would refer to it as his "boat."
Mr. Monk and the Genius - S7-E2
Character mistake: At the beginning when Monk is writing Natalie's check, we see a shot of it, but the I in "nine" isn't dotted. As meticulous as he is, Monk would never leave an I undotted (we've even seen him dot someone else's i) especially since it would bother him.
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.