Corrected entry: When Scott Calvin is wearing the Santa suit in the early part of the film, the coat has a strip of white fur down the front. However later, as Santa Claus in Dr. Miller's living room, when he gets arrested, the coat has two fur pom-poms down the front. And after he gets released and comes back to the house, there is only one fur pom-pom on the front of the jacket.
Corrected entry: At the beginning of the film, just as Scott Calvin takes over the Santa duties, he visits the house of a little girl named Sarah. Right before Scott rudely asks Sarah if she still wants the doll and flings it into her Christmas tree, Sarah asks Scott why he doesn't look like Santa, why he has no beard, etc. You can easily tell her two front top teeth are missing (loss of baby teeth). However, towards the end of the film and seemingly a year later to the date, Scott (now full blown as Santa Claus) visits Sarah's house again and he is now very kind to her. When she tells him that the milk she left him this time was soy milk, you can easily see her two front top teeth are still missing. Very unlikely a year later.
Corrected entry: When Scott is looking at the huge list of names with "Armand Asante" on it, you can see that the second page is the same as the first.