Warp stabilizer is a really great plug-in but not fault proof.
Outside of reshooting the scene, I would try changing the parameters in warp stablizer from “Smooth Motion” to “No Motion” and then stop the clip before the camera pans left. That way warp only effects the moment the boy runs past. At the exact same frame continue the rest of the shot in a second clip without warp stabilizer on it.
Hope that helps!
Josiah Burdick
fearlesspictures.com