Continuity: When sitting around the table with her friends, the book Katie is holding changes between shots.
Continuity: After the cop talks to Katie and he drops her off, she has a conversation with Harrison and her hair repeatedly jumps about between shots.
Errors made by characters (possibly deliberate errors by the filmmakers): At the AA meeting, Detective Handler says, "I'm Wade Handler; I'm a cop." Last names are not given at AA meetings, to preserve the anonymity of those present.
Continuity: Katie is studying in the library. She is writing with a pencil, and starts to nod off. She falls asleep for a second, and we see and hear her pencil drop onto her notebook, but in the next shot she is holding her pencil upright.