Yeah and it's not the socially best thing to announce it here before that, not giving mirrors time to sync (note: it's the master mirror and not download.freebsd.org for example). Also because theoretically there could be updated images uploaded still, causing chaos.
Also it doesn't make a lot of sense to link to a download mirror in first place.
Maybe the link should be changed to release notes or download.freebsd.org for a load balanced version.
Release Notes: