package: bridge-utils version: 1.6-3 severity: important justification: breaks network connectivity on release upgrade
It looks like this is a kernel change not a bridge-utils change. But the way MACAddress selection for the bridge works has changed between buster and bullseye. The result is that if you use dhcp based on mac address in a provisioning database to provision addresses on your servers (or presumably use an address based on IPv6 IID), your addresses will change potentially breaking network connectivity to your servers after reboot. I think the best solution to this bug is to document probably in news.debian and release notes the issue and how you can get the old behavior if that's what you need on upgrade.
