Hi, Today, we realized the bounce processing of mailman3 was broken and once we brought it back up, it started processing a huge queue of bounced mails. You are very likely going to receive lots of emails related to bounce processing (if you have it enabled, for example notification of unsubscription due to excessive bounce)
We are sorry for the inconvenience. Check https://phabricator.wikimedia.org/T282348 for more information.
Best