Audio problem: When the alien cuts Boris's shackles they hit the floor and make a metallic sound, yet when the chest armour falls it sounds like the foam object it really is made of. (00:03:40)
Audio problem: When Jeffrey Price asks J what is the plan, J replies "You're going to send me back to July 15, 1969." Two shots are shown as he says this line. The first shot shows a reverse angle of J starting to speak the line, however, his jaw is never shown moving. This line would require his jaw to move. (00:32:20)
Audio problem: After Boris shoots his spears at J, he jumps Boris and himself off the roof and goes back in time a minute to avoid being shot with the spears. When the spears miss him he says "Right! Left! Left! Right!" but his mouth is out-of-sync when saying "Left! Left!". (01:30:00)
Answer: Earlier in the movie, the way K was talking about Boris was different than what J had come to expect of his partner. So J wanted to know what happened between Boris and K at Cape Canaveral that changed him. So more of what did Boris do to K rather than just the report of what K did.