guix lister inconcistencies

softwareheritage-scheduler=>  select id from listers where name='nixguix' and instance_name='guix-backlog-20240220';
                  id                  
--------------------------------------
 eadece7c-bf18-42d7-891b-6c39582a3376
(1 row)
select url, enabled, last_seen, last_update from listed_origins where lister_id='eadece7c-bf18-42d7-891b-6c39582a3376' limit 10;
                          url                          | enabled |           last_seen           | last_update 
-------------------------------------------------------+---------+-------------------------------+-------------
 ftp://alpha.gnu.org/gnu/guile/guile-2.9.2.tar.xz      | t       | 2024-06-12 11:34:33.771869+00 | 
 ftp://alpha.gnu.org/gnu/guile/guile-2.9.3.tar.xz      | t       | 2024-06-12 11:33:18.129151+00 | 
 ftp://alpha.gnu.org/gnu/guile/guile-2.9.4.tar.xz      | t       | 2024-06-12 11:35:26.261608+00 | 
 ftp://alpha.gnu.org/gnu/guile/guile-2.9.5.tar.xz      | t       | 2024-06-12 11:35:00.532321+00 | 
 ftp://alpha.gnu.org/gnu/guile/guile-2.9.6.tar.xz      | t       | 2024-06-12 11:33:22.62926+00  | 
 ftp://alpha.gnu.org/gnu/guile/guile-2.9.7.tar.xz      | t       | 2024-06-12 11:35:22.568458+00 | 
 ftp://alpha.gnu.org/gnu/guile/guile-2.9.8.tar.xz      | t       | 2024-06-12 11:35:44.215333+00 | 
 ftp://ccrma-ftp.stanford.edu/pub/Lisp/snd-19.6.tar.gz | f       | 2024-06-18 23:54:15.583204+00 | 
 ftp://ccrma-ftp.stanford.edu/pub/Lisp/snd-20.5.tar.gz | f       | 2024-06-18 20:46:10.488559+00 | 
 ftp://ccrma-ftp.stanford.edu/pub/Lisp/snd-20.7.tar.gz | f       | 2024-06-18 20:38:33.06428+00  | 
(10 rows)