Audio problem: Just as McClane and Farrell are about to leave the Eastern Power Hub, Farrell goes on a long rant and his mouth does not match the words he is saying. [In the unrated version of the film, the rant concurs with Will's mouth movements, but the mistake is valid for the regular version.]
Audio problem: When Dakota and Jerrod start having sex, Aubrey's mother can hear Jerrod's moans through the ceiling. But up until they *really* start getting into the act, the moans that Susan is hearing don't match the shots in the bedroom.
Audio problem: Harrison hears Ro's phone yet it's on silent mode.
Audio problem: When Angel is having a go at Danny in the rain after Tim Messenger has been murdered, there is a shot of Danny over Angel's shoulder. In this shot you can see Angel's mouth isn't moving, but we hear him still shouting at Danny.
Audio problem: After Bert is shot in his car, when Bobby pulls up beside him and shouts, "Pop, pull over!" for the first time, in the next tight close-up of Bobby's face he is still shouting, but the only thing we hear is panting, until the next side shot. (01:17:00)
Audio problem: Justin Chatwin's character wants to kill himself. He grabs a breakaway double-barrel shotgun off the gun rack and steps around the corner. Then we hear a round chambered in a pump shotgun. (00:43:40)
Audio problem: Tom is in the van, after dropping off his daughter, and he "redials" a number on his cellphone but we hear the electronic beeps for each number being dialled, even though redialling on cellphones does not produce those sounds.