Comment 15 for bug 1864822

I looked into this issue today. I wasn't able to reproduce this issue on my local devstack setup.
The problem which I see (and You already mentioned) is that some rules with old cookie id stays in br-ex bridge. So maybe solution/workaround for that would be to add cleaning of rules with old cookie always when bridge was "re-created".
Normally it wouldn't be needed as when new bridge is created it will not have any OF rules, but maybe forcing to clean such leftovers would help neutron-ovs-agent to recover from such problem with connection to ovsdb.