In the beginning of the movie, when Luther Whitney (Clint Eastwood) is going to break in the house he wants to rob, a waning Moon is clearly visible in the sky.

Now go to the scene passed halfway in the movie when Kate Whitney (Laura Linney) is alone in her home at night.

Through the window you now see a full moon, but only two or three days went by in the story between the two scenes, so we should expect a Last Quarter Moon, not a Full Moon to be seen in the sky.