Katie calls and leaves a message on her neighbor's answering machine while at work at Ivan's on a Monday (according to the answering machine). When Kevin calls Ivan's and listens to the recording, it states that Ivan's is open Tuesday to Sunday, meaning it is closed on Monday.
When Detective Tierney drives away at the end of the scene with the police road block for the 4th of July Parade, the car has a front license plate as it begins to turn around. In the next shot of the front of the car there is no front license plate.
When Katie and Alex were talking in the canoe,over a 30 second period when the camera switches back and forth between Katie and Alex, Katie has shiny lipstick on, then no lipstick, then shiny lipstick again.
Near the beginning of the film, an aerial view of the bus taking Katie to Atlanta is shown traveling on the Linn Cove viaduct in western North Carolina. The Linn Cove viaduct is part of the National Park Service's Blue Ridge Parkway and is closed to commercial vehicles including buses.
During Katie's flashback, she clearly take both pie plates and the wine bottle to the kitchen, but only brings the wine bottle back to the dining room table. However the pie plates are clearly seen on the kitchen table when the husband returns home later in the movie.