Audio problem: In the scene where Leo explains how he launders the drug money and Roger says "You're a cheat", Leo says "Come on, everyone cheats a little, look at the pentagon." But when he says "look at the pentagon", it's dubbed in because the sound of his voice doesn't match his other dialogue, and if you read his lips it doesn't match either.
Audio problem: In the shoot out scene in the stilt house, Riggs is running up the stairs and falls - he has his Beretta in his hand, finger off the trigger, but you can hear it fire three shots. No one else is around or shooting at him, since the bad guys are on the run.
Answer: This scene is already in the movie (maybe only the Director's Cut). Riggs surfaces just off the pier, picks up a chain, strangles one man with it and breaks the other man's neck. The scene is cut considerably for play on television and in all versions of the movie in the UK prior to the 2010 UK blu-ray release (including the Directors Cut) - although some TV airings since 2000 have used the full uncut version.