As far as I know Couchbase doesn’t currently support doing a backup and restore if you are using sync gateway. There is always the chance that the last_seq doc is changed while the backup is run and isn’t the right value on the restored db. When this happens to us our whole DB is a little screwed up and not suitable for use. We tried a few times to create a prod copy server for performance testing using backup and restore but it never worked properly due to this issue.
Also, did you backup the sync_gateway bucket and restore it? I know there are only 2 docs in there but we usually back that one up and restore it too. Not sure if it’s required though.