Some rows are missing both client and server annotations

[mattmathis]

Approximately 50 rows per day are missing annotations

WITH NDT7data AS (
    SELECT id, a.TestTime, Server, parser.ArchiveURL, Client
    FROM `measurement-lab.ndt.ndt7`
    WHERE date BETWEEN '2022-01-01' AND '2022-04-20'
    AND server IS NULL
)

SELECT * FROM NDT7data

Finds 160,000 rows in for ~110 days (~300M tests). Both Server and Client are null.