MariaDB [nn]> alter table t engine='innodb';

Query OK, 0 rows affected (0.118 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [nn]> SELECT sum(0+0)-sum(0+0) from t;

+-------------------+

| sum(0+0)-sum(0+0) |

+-------------------+

|              NULL |

+-------------------+

1 row in set (0.000 sec)

MariaDB [nn]> alter table t engine='columnstore';

Query OK, 0 rows affected (0.094 sec)

Records: 0  Duplicates: 0  Warnings: 0

MariaDB [nn]> SELECT sum(0+0)-sum(0+0) from t;

ERROR 2013 (HY000): Lost connection to MySQL server during query

MariaDB [nn]>

Here are some variations on the same query:

MariaDB [nn]> select sum(null) from t;

+-----------+

| sum(null) |

+-----------+

|      NULL |

+-----------+

1 row in set (0.042 sec)

MariaDB [nn]> select sum(null)-sum(null) from t;

ERROR 2013 (HY000): Lost connection to MySQL server during query

MariaDB [nn]> select avg(null)-avg(null) from t;

ERROR 2013 (HY000): Lost connection to MySQL server during query

210518 12:38:21 [ERROR] mysqld got signal 11 ;

This could be because you hit a bug. It is also possible that this binary

...