Altering sequence to S3 leaves unremovable garbage behind

MariaDB [test]> create sequence s1;

Query OK, 0 rows affected (0.495 sec)

MariaDB [test]> alter table s1 engine=S3;

ERROR 1025 (HY000): Error on rename of './test/#sql-6beb_a' to './test/s1' (errno: 1 "Operation not permitted")

MariaDB [test]> show warnings;

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

| Level | Code | Message                                                                                     |

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

| Error | 1025 | Error on rename of './test/#sql-6beb_a' to './test/s1' (errno: 1 "Operation not permitted") |

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

1 row in set (0.000 sec)

MariaDB [test]> show tables;

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

| Tables_in_test |

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

| #sql2_3d73_4   |

| s1             |

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

MariaDB [test]> drop database test;

Query OK, 1 row affected, 1 warning (0.298 sec)

MariaDB [(none)]> show warnings;

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

| Level | Code | Message                                         |

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

| Error |  155 | Table test.@0023sql2_3d73_4 doesn't exist in s3 |

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

1 row in set (0.000 sec)

MariaDB [(none)]> create database test;

Query OK, 1 row affected (0.000 sec)

MariaDB [(none)]> show tables in test;

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

| Tables_in_test |

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

| #sql2_3d73_4   |

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

1 row in set (0.116 sec)