It's the `:OWNED_BY` relationships that seem to be producing the sort-of-but-not-quite duplicate keys we were seeing. The signer's UUID which is `r.RIssuerKeyId` (`{6}`) should probably be `r.RIssuerFingerprint` (`{7}`) instead.

I tired the following query, but got a *CMD Attempt to insert duplicate element* error from Neo:

```
MERGE (sig:Signature { uuid:{0} })
SET sig = { uuid:{0}, creation:{1}, expiration:{2}, state:{3}, packet:{4}, sig_type:{5} }
WITH sig
MATCH (signer:PubKey { uuid:{7} })
MERGE (sig)-[:OWNED_BY]->(signer)
```

Any thoughts, @jakewins?