Episode #3.2 - S3-E2
Character mistake: When Camille and Humphrey browse the writers' message board, the post done by Arnold Finch under the pen name of "Grumpywriter" contains a variety of spelling mistakes unbecoming of a writer (but that often happen in this show's prop department) such as "unnecasary" "tallentless imbecel." Earlier (hard to catch it without slo-mo in this case) in his mail we see him ask about puffer fish poison and "it's toxicity" and sign the mail with "Sincerly." The subject of another mail in the inbox is "Updated Shedule." (00:22:30)
Episode #3.5 - S3-E5
Character mistake: Fidel says that the victim "removed" the hard drive of his laptop, even pointing out an empty slot where the HD would be. During his massive overacting when he figures out of the solution of the case, Humphrey says that Jacob "wiped" the hard drive. (00:21:40 - 00:41:00)
Episode #3.6 - S3-E6
Character mistake: After a long day of various inquiries around the island and a lot of roaming and chit-chatting, DS Camille Bordey and DI Humphrey Goodman go back to the station wondering "if the photographs from Matthew Webster's camera have finished downloading." (00:23:50)
Answer: Most likely they had only tropical exotic drinks, he wanted an old fashioned English beer.