Continuity mistake: In the scene in DC, when Kay is walking in the park and encounters Dutch on the bench, we see a man in a black shirt with red lettering walk by twice behind the shots over Dutch's shoulder. You can also see the man at a further distance in the background and then closer on the next shot.
Continuity mistake: Midway through the film you can see the Washington Monument in the background with scaffolding for it's resurfacing. Later in the movie the scaffolding is gone. Yet the movie was released while the scaffolding was still up.
Continuity mistake: When Dutch is leaving Kay Chandler's hotel room after speaking to her for the first time it cuts to a side view of him and you can see a door and hinges behind him, though in actual fact the hinges are on the other side of the door frame and there should be no door behind him as Kay Chandler is holding it open on the other side.
Continuity mistake: When Dutch and Kay walk down the sidewalk on the way to the bar (in Miami), watch the woman in the white semi-transparent top. She and her boyfriend walk off the sidewalk, and four seconds later, they walk off the sidewalk again. (01:04:43)