The paint splatter patterns on the girls dress ate the end change multiple times.
When lois runs into malcolm at the school from the back of her you can see her start to lift her arm up but in the next scene her arm is down by her side again.
In the pre-title short Lois is cutting (coupons?) at the kitchen table. Reese walks in. In the first shot Lois has a short piece of paper in her hand. In the second, the piece of paper is noticeably taller.
The pink gym bag is already in the girl's house before Lois puts it in.
Dewey is bathing Reese. The suds on Reese's chest and collar bones change between shots.