Comment 23 for bug 1940425

https://review.opendev.org/c/openstack/neutron/+/865424 just disabled the test so that didn't fix anything
https://review.opendev.org/c/openstack/neutron/+/837780 was the actual patch that should have addressed the race between the bridge delete and the neutron agent.

regarding rodlfos latest comment

the destination port binding is created but not activated in pre live migration and it is activated onlyif the migration successeed in post live migration.

the trunk port should be in the active state in pre live migration.

the neutron l2 agent is expected to wire up the trunk on any host with a port biding associated with it active or inactive. there should be no depency on the port binding being active and the port status being set to active.

so if the neutron l2 agent is not setting the port stust to active and sending the network vif plugged event after the port bidnign is created and we plug the port in pre live migration that is a neutron bug.