iPhone 13 Pro videos shake/jitter and hear the lens focusing during playback

Hi. I’ve noticed when taking videos in which refocusing occurs automatically, when panning a scene or the subject is moving, I can hear the the lens focusing. During playback, I can hear a buzz/hum in the video, and it shakes/quivers like crazy during the focusing. For example while trying to video a snake swimming in our creek, it tried several times to focus on the snake, and the video shakes so much it’s practically worthless.