When Kyle and Jessi are playing pool, Kyle is supposed to hit only solids, but once he clearly hits the number 13, which is a stripe.
When Jessi is winning pool against Kyle, she just has the 8 ball left. Someone comments that it's the only pool ball left, and if she sinks it, she wins. The number 13 is visible, even though Kyle sank it earlier. Then in the next scene, the 13 ball is magically gone.
When Kyle challenges Jessi to a game of pool, he breaks and pots the 6 ball. In the next shot of Kyle shooting, he sinks a beautiful bank shot into one of the center pockets. The ball he pots? The 6 ball again! Kyle also sinks the 5-ball on 2 separate occasions, but since the shots are not consecutive and because the 5-ball and 3-ball can be easily mistaken for one another (the 5 is orange, the 3 is red), this goof is not quite as noticeable as the one with the 6 ball.
When Jessi is about to beat Kyle at pool, she tells him that she's giving him the 8 ball, which changes position before Kyle hits it. The cue ball also changes position.