A user (https://listenbrainz.org/user/petricordial) reported in IRC that their listens count was not updated even after a day when they submitted ~70 K listens using pylistenbrainz script. The listens were of the time period 2008-2020. I checked the database:

listenbrainz_ts=> select count('*') from listen where user_name = 'petricordial';
count
-------
61061
(1 row)

listenbrainz_ts=> SELECT SUM(count) FROM listen_count_30day WHERE user_name = 'petricordial';
sum
------
9522
(1 row)

Interestingly, the cache shows the number of listens as 10145.

The user's listen data and import scripts are also available at https://github.com/joshuacwnewton/listening-history .