I can't see the definition of IPFIX_FIELD_natEvent in the source code and in the raw output. Is it going to be added as an IPFIX output?
In the link below I can see its reference number.
IPFIX_FIELD_natEvent = 230
https://github.com/cloudflare/goflow/blob/ddd88a7faa89bd9a8e75f0ceca17cbb443c14a8f/decoders/netflow/ipfix.go