When Mr. Monk retells the joke about the psychiatrist, the psychiatrist at the table behind him rubs his ear. In the next shot, he holds a book in his hand, and in the next shot after that, he rubs his ear again.
When the wine hostess describes the "Spit" step to Monk, his glass of water switches from his right hand to his left and back between shots.
When Monk was at the table, he made a big deal about the plates on the other side to stay on the table, but when Larry gets his wine, the plates are gone.
When Zwibell sits at Monk's table, he orders the 'Degout Pinot' wine. However, the label on the bottle says 'Allacco', presumably the same as the 'Allacco Cabernet' that Monk ordered.
When Monk is drinking with Nicoletti, he ends up with only a little left in his glass and his carafe is empty. A few shots later, his glass has more wine in it.
The woman leading the wine tasting describes the new Cabernet Sauvignon as "slightly softer and more tannic". The two terms are not compatible. Tannins give a wine sharpness and astringency, the opposite of softness.
The postmark on Rudy Schich's postcard is clearly a fake. It consist only of the usual parallel wavy lines, but with no details of time, date and place of issue.
When Monk turns the page of the hotel register, past the previous day when he and Natalie signed in, the pages are blank. The register would be ruled into lines and columns, for (at a minimum) date, room number and name. The previous pages were also not ruled, which is unusual.
When Mr. Monk exits his room the morning after the group photo is taken, a grip C-stand is visible on the right hand of the screen. In the wide shot, it is gone.