Roman, only N->(N+1) upgrades are supported - you can't skip Kilo: you should do Juno->Kilo, then Kilo->Liberty upgrade instead.
Based on the discussion in https://bugs.launchpad.net/nova/+bug/1511466 my understanding is that the reporter forgot to force data migration of remaining instances (db sync only migrates DB schema and does not touch DB rows for availability sake).
Roman, only N->(N+1) upgrades are supported - you can't skip Kilo: you should do Juno->Kilo, then Kilo->Liberty upgrade instead.
Based on the discussion in https:/ /bugs.launchpad .net/nova/ +bug/1511466 my understanding is that the reporter forgot to force data migration of remaining instances (db sync only migrates DB schema and does not touch DB rows for availability sake).