mysql.slow_log reports incorrect start time

MariaDB [test]> truncate mysql.slow_log;

Query OK, 0 rows affected (0.00 sec)

MariaDB [test]> select current_time(); select sleep(10); select current_time();

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

| current_time() |

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

| 17:24:37       |

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

1 row in set (0.00 sec)

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

| sleep(10) |

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

|         0 |

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

1 row in set (10.00 sec)

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

| current_time() |

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

| 17:24:47       |

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

1 row in set (0.00 sec)

MariaDB [test]> select start_time, sql_text from mysql.slow_log;

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

| start_time                 | sql_text                |

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

| 2016-12-21 17:24:15.320518 | truncate mysql.slow_log |

| 2016-12-21 17:24:37.593565 | select current_time()   |

| 2016-12-21 17:24:47.595008 | select sleep(10)        | <-- Start time is ~10sec after previous command

| 2016-12-21 17:24:47.596239 | select current_time()   |

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

4 rows in set (0.00 sec)