Other mistake: When Jackie is falling through the trees at the beginning, you can easily tell he is on strings because he would hit the branches with a lot more force than he does, and also wobbles in certain ways which would be impossible to do in this situation.
Other mistake: During the final fight on the roof, it is possible to tell that one of the two bad guys is played by two different actors. The first time Jackie fights the one wearing the waistcoat, you can clearly see the actor's face. However, when the bad guy jumps over an air vent, doing a spinning kick, look at his face and you will see it is a different actor. In addition to this, it is possible to see that the second actor is shorter.
Other mistake: When the helicopter crashed it was near a forest. When Jackie finds it later on it is in the middle of a desert.
Other mistake: When Jackie is running in the wooden shoes he sees a dog falling from a piano being raised in the air. In two of the four shots that the dog is seen falling, you can see that it is a doll.
Other mistake: When Jackie and some people find a dead guy in a tree one of the villagers says something to Jackie. He not only understands this, he says something back to him. A few minutes later he is speaking the language also. After being their only a few days, Jackie knows their language.
Answer: It's quite possible because most movies use dubbing (or "looping") as part of the post-production work to enhance the quality or fix minor sound problems. Sometimes a different actor's voice is dubbed over a minor on-screen character.
raywest