Plot hole: The FBI is looking for a "very tall" guy who has been identified as such by various witnesses and by their own expert due to the entry angle of a fatal bullet wound - 6'5" at least. They send Elena into a bar near the end of the show to meet the Albanian perp who when he arrives is barely average height.
Revelations - S3-E6
Continuity mistake: When Tim puts Lucy in the squad car after "arresting" her, the rear door on the driver side is open, but when the camera pans back to her it's suddenly closed without making a sound.
Revealing mistake: When Harrow and Nicholls are in what is supposed to be Queensland Police Headquarters, a window is visible with logos for Radio National and Triple J behind them. This shows that the scene was recorded at the offices of the Australian Broadcasting Corporation. (00:31:04)
Continuity mistake: Rick pulls up in a car to the right side of a helicopter, gets out, and gets in the helicopter. When the helicopter is shown taking off, there is no car next to it. (00:38:20)
Episode #1.1 - S1-E1
Factual error: This is set in 1933. When the killer comes back to his lodgings in episode 1, Lily on the stairs is humming "Somewhere over the rainbow", which was written for The Wizard of Oz in 1939. She also happens to wear bright red shoes, which feels like yet another Wizard of Oz reference. Interesting enough, the subtitles say that she is humming a different song, "Night and day" which she openly sings throughout the series and was already a hit in 1932. (00:44:10)
Character mistake: When the bodyguards enter elevators, they always enter last; they should be entering first to ensure it is secure. This is particularly visible in the hotel where the elevator can stop on any floor and Special Protection Branch does not have complete control of it as an express.
Revealing mistake: In the morgue the wall has fake body chambers. Look at number 6 and Boyce the wall stops and a door behind it.
Continuity mistake: John Paul Getty approaches the kidnapper's cars and Getty removes his sunglasses and tucks them into his coat pocket. The next shot shows him still wearing them as the kidnappers approach.
Continuity mistake: At breakfast the apple being cut for Camille as she poses a question to Adora is suddenly on her plate as the scene cuts to Adora's immediate reaction. (00:05:07)
Fear and Loathing in Beverly Hills - S2-E8
Continuity mistake: In one part of the scene where Joe has Delilah's iPhone and it's ringing, it shows the call with a green answer button and a red decline button, then, it shows it only with a slide to answer option. (00:53:00 - 00:59:00)
Episode #1.6 - S1-E6
Continuity mistake: The paramedics zip up a red body bag containing Helen, who was killed in the fire. But they wheel out a black body bag a few minutes later.