Character mistake: When Troi is talking with Picard and Dr. Crusher about what's wrong with her mother, she says that "something was happening in her metaconscious mind." Dr. Crusher then asks "metaconscious?" As a Star Fleet doctor, she's had to study the neurology of Betazoids, Vulcans, and other telepaths. She should be familiar with the concept. (Yes, it's expository dialogue for us, the audience, however, Picard is in this scene too and it would have made more sense for him to ask about it.) (00:17:55)
Character mistake: When Data and Picard discover Troi in her bathtub, Data scans her and comments that she is technically no longer "human." While Troi is indeed half human, she has the features of a Betazoid (black eyes and empathic abilities) and consistently describes herself and is described by others as a Betazoid. It is unusual for anyone to describe Troi as being "human", and it is unfathomable that Data would make that mistake.