Just tried launching a bullseye instance on deployment-prep. Puppet fails early enough that I have no sudo on the instance.
The failure is Repository 'http://mirrors.wikimedia.org/osbpo bullseye-zed-backports InRelease' changed its 'Origin' value from 'Infomaniak' to 'Mirantis'.
This seems to be coming from ::profile::base::labs where profile::base::labs::unattended_osbpo is set to "present" in hieradata/cloud.yaml.
Sure enough, https://mirrors.wikimedia.org/osbpo/dists/bullseye-zed-backports/InRelease shows Origin: Mirantis (but is signed)
full run in case it's helpful P59106