Empty string not accepted as DEFAULT value for non-empty tables

MariaDB [test]> CREATE TABLE person (

    ->     name VARCHAR(100) NOT NULL,

    ->     surname VARCHAR(100) NOT NULL

    -> ) ENGINE ColumnStore;

Query OK, 0 rows affected (0.222 sec)

MariaDB [test]> INSERT INTO person (name, surname) VALUES ('Miles', 'Davis');

Query OK, 1 row affected (0.160 sec)

MariaDB [test]> ALTER TABLE person ADD COLUMN middle_name VARCHAR(100) NOT NULL DEFAULT '';

ERROR 1815 (HY000): Internal error: New column has to have a default value if NOT NULL required.

MariaDB [test]> ALTER TABLE person ENGINE InnoDB;

Query OK, 1 row affected (0.303 sec)               

Records: 1  Duplicates: 0  Warnings: 0

MariaDB [test]> ALTER TABLE person ADD COLUMN middle_name VARCHAR(100) NOT NULL DEFAULT '';

Query OK, 0 rows affected (0.038 sec)

Records: 0  Duplicates: 0  Warnings: 0