In the brothel scene after the opening credits when Fox is watching Sandy, the microphone very clearly scrapes or bumps into something, as there is a very loud, scratchy sound that can be heard briefly.
X's futuristic device is in fact a Palm Pilot with video being projected onto it. This is visible in close ups.
After Fox and X meet with Hosaka, they are talking while walking up to a restaurant. Fox's mouth does not match what he is saying at all. And when X responds, his mouth isn't even open.
When X meets with the enforcers and we hear the man say "Come on, let's go spend some of your unlimited money," his lip movement does not match this.
When X is talking to the owner of the lab in Marrakesh, the man says: "I got this lab. It was used for heroin in the old days." When he says this, his lip movement does not match this.