When Brian tackles the woman, she loses a slipper, then loses the other when she kicks Brian, then it reappears.
When the Canadian approaches Brian and Stewie who as beside the road, there is no visible carnage that was created earlier.
In the overview scenes, Cleveland's former house is nowhere to be seen.
When "All I really want for Christmas" is playing, it starts outside the Griffin's house with the car outside the garage but when the Griffins come outside, the candy cane and snowman have moved and the car is gone.
When Brian and Stewie drag Dan into the closet, he leaves a thick trail of blood. When they close the door, the blood is no longer there.