Video prompt: A flock of birds migrating in a perfect V-formation across the open sky, the sun setting behind them.
Defect: Deformation (when Object is involved in an act,  anything in this process that's weird. e.g. people walk into a wall. "Walk" is an act)
Explanation: The birds unnaturally merge with one another, which is unrealistic, as they should maintain distinct, separate forms while in motion.