Audio problem: When the Knights deploy their missiles with no results, we see in close-ups as they respond that Steven is Knight 1, Jimmy is Knight 7, and another Marine is Knight 3. After Steven says, "Knight 1. Sweet Luck. Echo, Fox 2," we see a close-up of Knight 3 and hear his voice (not Jimmy's) say, "Knight 7, Fox 2", though he is in fact Knight 3, and Jimmy is Knight 7. (01:00:45)
Audio problem: At the White House, when Connie hangs up on David, as the President stands at the podium behind her, his mouth and the words we hear are not in sync. We are seeing and hearing him live, not on a delayed news feed. (00:28:15)
Audio problem: The same female scream can be heard three times during the first attack by the aliens. It is first heard in the scene when Jeff Goldblum is riding his bike to his father's house. The second time it is heard right as Jeff gets to his father's door. The third time is in Los Angeles when the people are running away. It's a very distinct scream.
Audio problem: After David's rant about burning the rainforests, etc, when he's on the ground Julius takes the bottle out of David's hand and we hear the sound of the bottle hitting the floor. But Julius still has the bottle in his hand, then puts it down two shots later - with no sound obviously. (01:35:30)
Audio problem: After the President tells General Grey that he is a combat pilot who belongs in the air, Major Mitchell says, "Okay, sir," but his mouth movements are not in sync. (01:57:40)
Audio problem: In the car with Julius, we hear David say, "Hey, hey slow it down," but his mouth actually says, "Hey, hey what have..." (00:40:25)
Audio problem: Aboard the USS Georgia in the Persian Gulf, when the Captain stands beside the submarine sailor who says, "Sir, we're looking at a total radar block out over a 13 kilometer area," the words we hear are not in sync with the reflection on the screen in front of him.
Answer: Remember that the aliens had to interface with our satellite computer code first...David simply "reverse engineered" the code to create the virus. When it was uploaded, they didn't have enough time to combat it.