Reproducible server crash after the 2nd ALTER TABLE ADD FOREIGN KEY IF NOT EXISTS

CREATE DATABASE IF NOT EXISTS forgedImei;

USE forgedImei;

CREATE TABLE IF NOT EXISTS imei (

  id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,

  imei VARCHAR(16) NOT NULL UNIQUE KEY,

  problem ENUM( 'D', 'I' ) NOT NULL,

  provInEir ENUM( 'no', 'yes' ) NOT NULL

    COMMENT "'yes' means IMEI can be provisioned in EIR."

);

CREATE TABLE IF NOT EXISTS imsi (

  id INT UNSIGNED NOT NULL AUTO_INCREMENT PRIMARY KEY,

  imsi VARCHAR(16) NOT NULL UNIQUE KEY

);

CREATE TABLE IF NOT EXISTS pair (

  imei INT UNSIGNED NOT NULL,

  imsi INT UNSIGNED NOT NULL

);

ALTER TABLE pair

ADD FOREIGN KEY IF NOT EXISTS (imei)

REFERENCES imei (id)

ON DELETE CASCADE

ON UPDATE CASCADE;

ALTER TABLE pair

ADD FOREIGN KEY IF NOT EXISTS (imsi)

REFERENCES imsi (id)

ON DELETE CASCADE

ON UPDATE CASCADE;