Are there messages with Date: headers in the last month?
Well, there are definitely many messages from the last month.
Hyperkitty, for each message, shows in the upper-right hand corner of the message "30 May 2024" "29 May 2024" "20 May 2024 3:00pm" and so on. Each message has a date shown.
"Threads by Month" is populated with messages from the last month.
"All Threads" is populated with messages from the last month.
However, "Recently Active Discussions" is empty.
That is not conclusive regarding "Date: headers". But wouldn't "Threads by Month" use the same date information?
By the way, during the import "Message 04b901d993ca$d6cf3180$846d9480$@gmail.com failed to import, skipping" and "psycopg2.OperationalError: SSL connection has been closed unexpectedly".
However, the import continues past those errors. For example:
Computing thread structure Synchronizing properties with Mailman INFO hyperkitty.lib.mailman 10820 emails left to refresh, checked 1000 10820 emails left to refresh, checked 1000 INFO hyperkitty.lib.mailman 10820 emails left to refresh, checked 2000 10820 emails left to refresh, checked 2000 INFO hyperkitty.lib.mailman 10820 emails left to refresh, checked 3000 10820 emails left to refresh, checked 3000
It all eventually completes with exit code 0. Generally, successful. So it's unclear if a skipped message is the cause.