Mysql – Rows not updated in transactions without any errors

I have a stored procedure that updates a user's balance and inserts a transaction log. I don't know why, but sometimes it doesn't update the users table.

Stored Procedure Code

DELIMITER $$
USE `db_name`$$
DROP PROCEDURE IF EXISTS `update_balance`$$
CREATE DEFINER=`username`@`%` PROCEDURE `update_balance`
    (IN balancechange INT,
     IN userid INT,
     IN tableName VARCHAR(100),
     IN `type` INT,
     IN description  VARCHAR(1000) CHARSET utf8,
     IN trans_id VARCHAR(150))
BEGIN
START TRANSACTION;
SET @tmp = (SELECT id FROM users WHERE id = userid FOR UPDATE); 
UPDATE users SET gold = @gold := ((@oldbalance:=gold) + balancechange)
    WHERE id = userid AND (gold + balancechange) >= 0;
SET @countRow =  ROW_COUNT();
IF (@countRow > 0) THEN
    SET @t1 =CONCAT("INSERT INTO ", tableName,
                    " (user_id, type, balance_change, old_balance, new_balance, description, trans_id)
                    values ('", userid, "', '", `type`, "', '", balancechange, "', '", @oldbalance, "', '", @gold, "', '", description, "', '", trans_id, "')");
    PREPARE stmt3 FROM @t1;
    EXECUTE stmt3;
    DEALLOCATE PREPARE stmt3;
    SELECT @oldbalance AS oldbalance , @gold AS gold,
           balancechange, 0 AS result;
ELSEIF (balancechange = 0) THEN
    SET @oldbalance = (SELECT gold FROM users WHERE id = userid LIMIT 1);
    SET @t1 =CONCAT("INSERT INTO ", tableName,
                    " (user_id, type, balance_change, old_balance, new_balance, description, trans_id)
                    values ('", userid, "', '", `type`, "', '", 0, "', '", @oldbalance, "', '", @oldbalance, "', '", description, "', '", trans_id, "')");
    PREPARE stmt3 FROM @t1;
    EXECUTE stmt3;
    DEALLOCATE PREPARE stmt3;  
    SELECT @oldbalance AS oldbalance , @oldbalance AS gold,
           0 AS balancechange, 0 AS result;
ELSE 
    SET @oldbalance = (SELECT gold FROM users WHERE id = userid LIMIT 1);
    SELECT @oldbalance AS oldbalance , @oldbalance AS gold,
           0 AS balancechange, -1 AS result;
END IF;
COMMIT;
END$$

DELIMITER ;

Usage

CALL update_balance(1000, 123, 'user_transaction201806', 1, '{$desc}', '123456789')

The users table is InnoDB, the user_transaction201806 is MyISAM.

Sometime the data for a user isn't updated in the users table, but the data for a user is still added in the relevant transaction table (e.g. user_transaction201806) with correct data.

Because the table containing the user's transactions is in myISAM format, the transaction cannot be rolled back.