There appears to be data missing from the biweekly sqlite exports.
However, in the sqlite dumps from 2026-01-15, 2026-01-01, and 2025-12-01, two of the issues have NULL for brand_id:
sqlite> select number, variant_name, no_brand, brand_id from gcd_issue where series_id = 3406 order by sort_code;
number variant_name no_brand brand_id
------ -------------- -------- --------
1 Direct 0 2654
1 Newsstand 0
2 0 2654
2 Third Printing 0 2654
3 Direct 0 2654
3 Newsstand 0
4 Direct 0 2654
4 Newsstand 0 2654
Mike