Audio problem: When Kevin and his crew of thieving little people land in the Middle Ages, Randall informs Kevin that they made all of what's surrounding them, trees, shrubs, bushes etc. Kevin's reply is "Phew, that's not bad" He says this without opening his mouth. This was looped into the film later on.
Audio problem: The four jerry cans of fuel Max is carrying are in fact plastic and made to carry water. They have screw on caps and smaller breather caps. When the jerry cans are dropped they make the sounds of metal ones.