My Scheduled Jobs Log doesn't display a date or time
The run_time field is set to current timestamp by default and its a not null field which mean that run_time will never NULL values. Can you please check you schema for civicrm_job_log. I am pasting below for CiviCRM version 4.7.29

mysql&gt; DESCRIBE `civicrm_job_log`;
+-------------+------------------+------+-----+-------------------+-----------------------------+
| Field       | Type             | Null | Key | Default           | Extra                       |
+-------------+------------------+------+-----+-------------------+-----------------------------+
| id          | int(10) unsigned | NO   | PRI | NULL              | auto_increment              |
| domain_id   | int(10) unsigned | NO   | MUL | NULL              |                             |
| run_time    | timestamp        | NO   |     | CURRENT_TIMESTAMP | on update CURRENT_TIMESTAMP |
| job_id      | int(10) unsigned | YES  |     | NULL              |                             |
| name        | varchar(255)     | YES  |     | NULL              |                             |
| command     | varchar(255)     | YES  |     | NULL              |                             |
| description | varchar(255)     | YES  |     | NULL              |                             |
| data        | text             | YES  |     | NULL              |                             |
+-------------+------------------+------+-----+-------------------+-----------------------------+
8 rows in set (0.00 sec)