Continuity mistake: Henry does the whole Sherlock Holmes thingy deducing specific aspects of people's lives based on observation. Easy one with Maggie, guessing she's divorced. When he explains how he guessed it, her hand holding the glass from above changes position between shots. (00:07:55)
Continuity mistake: Maggie's clumsiness burnt the tasty dish, but the gourmet detective hands her and her unlikely date a spare portion. During the sequence that follows, her fork switches hand and is lowered or raised without continuity between cuts. (00:06:25)
Continuity mistake: Henry's assistant mentions Duquette calling; she has her arms lowered seen from behind, but when she replies that he didn't say the reason, she is holding the phone in front of her chest. (00:03:20)
Continuity mistake: Maggie arrives home and puts the shopping bags and her handbag on the kitchen isle, next to her daughter. The handbag rolls sideways, but in the following shot it is straight and with its strap adjusted differently. (00:03:00)
Factual error: For being set in the spring in San Francisco, the trees (look at Maggie coming back home in the intro) are rather barren and there are dead leaves in the grass.
Factual error: When Henry looks at the boat photo at Layton's, the ZIP code of the paper above is the proper one for San Francisco, but the calling card nearby has a nonexistent one, 90344 (together with the usual bogus 555 phone numbers). (01:04:20)
Factual error: Ian and Sally's photo at the fundraiser is supposed to be from one week "earlier", so before the murder; the date on the cheque is 06-05-11, though, which would be 4 years prior the year the movie is set in. Further confirming the mistake, the murder happened "on the 12th" (no month specified, but then has to be either May or June) and the day after is a Saturday (the book presentation), both not compatible with this timeline. (00:51:40)
Character mistake: During their bickering about the coffee, the idea is that the officers just drank some coffee made from beans coming from excrements of rhesus macaque. That's how the civet coffee is made; macaques merely chew and spit the beans, they do not 'process' them (that'd be the kopi luwak that he references immediately after). (00:27:00)
Other mistake: Captain Forsyth is looking at the dossier about The Gourmet Detective; the interrogation happens in the evening with everyone still dressed for the formal dinner, but the file was printed at 9 AM. There's no reason why the police would have printed that file at that time of the day. (00:23:15)
Factual error: The food expert protagonist says, and it's the key plot point, that lamprey is deadly if not prepared properly, due to the natural toxins it contains. Simply put, it's not the case.
Factual error: Set in San Francisco, the main female character keeps referring to herself (and so do others addressing her) as "Detective Maggie Price." San Francisco is the one place in the US where the correct designation for a detective is "inspector."
