Audio problem: At the end of the movie when Tom Hanks is in the lake house, and throughout the whole lake scene, the sound of the lake is not synchoronised to the movement of the waves. Must have added the sound of the waves after.
Audio problem: In the scene where Michael Sullivan robs his first bank before the montage and is in the manager's office, Michael offers him a little present. Sullivan says, "Call it a handling charge," and the camera is focused on the manager, but the words aren't matching what Michael Sullivan is mouthing.
Audio problem: When Tom Hanks ecapes from the hotel and Jude Law is shooting at him out of the window, you can clearly see a flash from Jude Law's gun but no sound.
Answer: He was doing a hot rail. If you heat up cocaine in a glass until it burns, you then inhale the smoke left behind.