Why do objects placed in perspective flicker?

I tried to use Mediapipe to track faces in perspective. I passed the Quest 3 camera image to Mediapipe to get the positions of facial key points on the screen, then used the ray from EnvironmentRaycastManager to get the coordinates of the key points in the scene, and then placed a ball model that tracks the key points to act as the head. However, the ball model flickers after being placed. I think it's because the tracking key points move too fast, causing the ball model to flicker. So I used SmoothDamp for smooth movement, but the flickering still occurs. I don't know why this is and how to solve it.