src/Exceptions/ApiExceptionHandler.php
private function handleModelNotFound(ModelNotFoundException $e)
    {
        $e = new NotFoundHttpException($e->getMessage(), $e, $e->getCode());
        return $this->handle($e);
    }
private function handleModelNotFound(ModelNotFoundException $e)
    {
        $e = new NotFoundHttpException($e->getMessage(), $e, $e->getCode());
        return $this->handle($e);
    }
Replace model not found exception to guarantee 404 error instead of 500

@param ModelNotFoundException $e Original exception to wrap and handle
@return Response