Hello,
Once last week and again earlier today we've had instances of erroneous notices being sent out to the AlmaLinux Announcement mailing list subscribers citing removal from the list due to too many bounces.
The underlying issue was indeed bounces - but not on the end of subscribers. We are partnered with an email delivery service which we relay all messages through and they have automatic rate limits in place which scale based on historical sending statistics. This doesn't play too nicely with the very bursty nature of a mailing list when a lot of posts hit the list at once, as was the case this morning when 11 Security Advisories hit the list together. Multiply 11 by the number of subscribers to the announcement mailing list and we had many thousands of messages hitting our partners relay at the same time. Their system automatically flagged this as suspicious and enacted a rate limit. That rate limit shows up to the mailing list software as a bounce, thus resulting in the emails everyone received.
Since many people did not get the proper announcements due to the issues, the details of the security advisories, including the 11 from this morning, are always available at https://errata.almalinux.org in addition to the mailing list archives https://lists.almalinux.org/archives/list/announce@lists.almalinux.org/.
We have since fixed everyone's subscriptions and tweaked our MTA's (Postfix) configuration to help limit the volume of email leaving the list server at any given time while working with our partner to make sure the relaying can happen quickly and efficiently without getting blocked or falsely triggering rate limits on their end.
We understand the importance of timely Security Advisory notices as well as keeping this list as low-volume and worry-free as possible for subscribers and apologize for any confusion or inconvenience this has caused.