Audio problem: An early scene in the movie has Chinese soldiers recruiting Tibetans to work on a secret project which they are told is a dam. As the scene ends, the sound of explosives draws everyone's eyes towards the mountains, where the explosions can be seen several miles in the distance. The sight and sound of these explosions take place simultaneously. Sound travels much slower than light. In reality, there should have been some delay before the sound of the explosions was heard.
Audio problem: When Langdon is in the Vatican archives for the second time and they are running out of oxygen, He uses the Swiss Guard's gun to shoot the glass. The problem being it takes roughly 0.8 seconds from the time the sound of the gun goes off to have any impact on the glass. He is no further than 5 metres from the glass, but still, this should be instantaneous.
Audio problem: As Shelton is about to drive away from City Hall, we see him operate a lever on the steering column of the van and we hear the familiar sounds of a transmission shifter clunking through a few settings into "Drive". The problem is that he used the lever on the left side of the column, which is the turn signal lever. The transmission shift lever is on the right side of the column. In reality, Butler used his left turn signal before steering left into the travel lane, and the sound editors added the shifter sound to try and cover the fact he's never actually seen putting the van into gear in the scene. (01:31:50)
Audio problem: Steve and Kate are sitting on the couch after dinner out with friends, Steve goes to kiss Kate and with her mouth completely closed you hear her say "stop." It's a voiceover and wasn't said in the moment because her mouth is closed kissing Steve. (00:46:55)