Revealing mistake: The compound Heptan-2-one is mentioned several times in this episode. The actress concerned persists in pronouncing the last syllable 'one' as in the number 1, whereas its correct scientific pronounciation should be as in the word 'bone' ie. sounds like 'own'. Nitpicking certainly, but a dead giveaway to any viewer with a basic knowledge of chemistry.
Revealing mistake: Almost all fingerprints throughout the whole show match by 99.32 percent. I have personally tracked it through series 6, 7, 8 and 9 and almost no fingerprint checks resulted in a different match. (Whether this has started in earlier series has to be confirmed).
Revealing mistake: Season 4, episode 21: "Dead Air". At the start, when Horatio looks at the call details, it very clearly reads "no sim card inserted" at the top of the screen. Quite hard for the accidental recipient of the call to have a working phone without a sim card...
Revealing mistake: When Phoenix bursts into flames on stage during her concert, the burn proof suit the stunt person is wearing (dressed as Phoenix) can be seen (her legs are very thick and her knees have deep wrinkles as well as the suit hem at her ankles can be seen).
Revealing mistake: In episode "Triple Threat": at the end of the episode when the triplets are being walked out of the building all in a row after being charged with murder, they have their hands behind their backs like they are in handcuffs. When Beth turns around to look at Noah, you see Ashley in front of her with her fingers laced together and no hand cuffs, getting into the van.