When the message is an IPv4 message, the GeoIP fields for ASN, Country and City are created and added so that you can search on them and display them on the Map.
When the message is an IPv6 message, the GeoIP fields are NOT created.
I can load the message and test it against the "SourceIP geo-lookup-city " extractor and it shows the city, same for "SourceIP geo-lookup-asn" and the "SourceIP geo-lookup-country" extractors.
It just not seem to add them when the messages are being processed.