During the flashback scene where Charlie is in the bathroom, he opens a bag of heroin that was closed with a yellow rubber band. While he is taking pinches of the drug and rubbing it inside his mouth, the rubber band goes from being loosely over the first two fingers of his left hand, to being wrapped twice around his index finger, back to being loosely over the first two fingers again.
After Sayid and Sawyer finish fighting, Michael hands Jack a pair of handcuffs. After that, while Sawyer is shouting, in one scene his sleeves reach his wrists, then they are folded, then they are back down to his wrists.
After Sawyer kills the polar bear, Boon says something like "Is this what killed the pilot?". But he doesn't know anything about it, the only people who know that the pilot was found alive and then killed by a monster were Jack, Kate and Charlie.
Not a goof: considering that Charlie immediately replies " No. No, that's a tiny, teeny version compared to that", it is obvious that the pilot's death had been discussed earlier, off camera. I tried to post the episode's transcript as proof, but I got a message saying that you don't publish URLs. So, here's the dialogue in question from the Quote page: www.imdb.com/title/tt0636290/quotes/qt0449248
During the flashback with Kate and the Marshall, his mouth movements do not match when he says "Really? This ought to be good."