*** Bug 1994274 has been marked as a duplicate of this bug. ***
This is worked around in upstream neutron by ignoring the KeyError. It is produced solely to create a return value that we don't use. The ultimate issue is solved in python-ovs by this patch: https://patchwork.ozlabs.org/project/openvswitch/patch/20210901161526.237479-1-twilson@redhat.com/
According to our records, this should be resolved by python-networking-ovn-7.4.2-2.20220409154849.el8ost. This build is available now.