During a scene in court, the color of Kathleen's suit changes.
When Kathleen writes "HELP ME" on the chalkboard it is roughly in the center of the board and written somewhat lightly. A few seconds later as the suspect is writing, the words "HELP ME" are now way over to the right, written much darker and is not in the same handwriting.
When Kathleen first realizes Carl is deaf and hands him a pen to write with, as she hands it to him and we are facing her it is top downwards in her hand, in the reverse shot it is top upwards with the cap on, as Carl takes the pen it is top upwards with the cap off.
At 1:23 into the movie, when she is checking keys against file cabinets at the Justice dept., the key won't fit into one of the file cabinets, then the key fits the very next one. This is minor but would not happen. Since the file cabinets are identical, they key would at least FIT the lock (though it wouldn't turn the lock mechanism) unless it were the correct key. For example....all Master Lock keys (of the same sort) will fit the intended item perfectly - it just won't unlock it unless the pins match.
Towards the beginning of the movie, when Carl Wayne Anderson is brought into court to be indicted, Cher's character (and his future attorney) is seen walking out of the courtroom, in fact she has to avoid running into him as he is being pulled into court by the cops. But less then one minute later, she is assigned to be his public defendant by the judge, however he is sitting behind The Bench, which is nowhere near the door out of the courtroom and she is shown just starting to walk away from him.
As can be seen in reflections in Kathleen's glasses in the library scene, the lenses are flat and therefore fake.
When Kathleen is reading Carl's case file after he attacks her, we hear her say "Can't they read?" but her lips are clearly saying something completely different.
Liam Neeson, an Irish actor, plays a character is from America. However, when he's asked to spell out an identifying tattoo of another person he spells the words "Jesus the saviour," though when the actual tattoo is later revealed, the word is spelled the American way, "savior."