While looking at BigQuery data I found an afe_job entry in BigQuery table is different from that of the original table.

http://cautotest/afe/#tab_id=view_job&object_id=198899956

SELECT
  kv.key
FROM
  `google.com:chromeos-lab.ci_results.afe_jobs20180510` j,
  j.keyvals kv
WHERE
  afe_job_id = 198899956
;

Row	key	 
1	builds	 
2	cidb_build_id	 
3	cidb_build_stage_id	 
4	parent_job_id

MySQL [chromeos_autotest_db]> select `key` from afe_job_keyvals where job_id = 198899956;
+---------------------+
| key                 |
+---------------------+
| cidb_build_stage_id |
| builds              |
| cidb_build_id       |
| parent_job_id       |
| build               |
| suite               |
| experimental        |
+---------------------+
7 rows in set (0.18 sec)