SELECT and DELETE/UPDATE return inconsistent row counts with identical WHERE clause

-- SCHEMA

CREATE TABLE orders (

    id          INT,

    user_id     INT,

    amount      DOUBLE,

    status      VARCHAR(20),

    created_at  TIMESTAMP NULL

);

INSERT INTO orders VALUES

(1, 1, 100.00, 'paid',    '2022-02-01 09:00:00'),

(2, 1, 200.50, 'shipped', '2022-02-02 10:00:00'),

(3, 2, NULL,   'failed',  '2022-02-03 11:00:00'),

(4, 3, 50.00,  'paid',    '2022-02-04 12:00:00'),

(5, 5, 999.99, 'paid',    '2022-02-05 13:00:00');

-- TRIGGER SQLs:

SELECT COUNT(*)

FROM orders

WHERE LPAD(

        LTRIM('v0px'),

        orders.id

      ) < LEFT('tutl', orders.user_id);

-- RESULT: {4}

DELETE FROM orders

WHERE LPAD(

        LTRIM('v0px'),

        orders.id

      ) < LEFT('tutl', orders.user_id);

-- affected_rows: {1}

UPDATE orders set 

  id = orders.id, 

  amount = orders.amount

WHERE LPAD(

        LTRIM('v0px'),

        orders.id

      ) < LEFT('tutl', orders.user_id);

-- affected_rows: {1}