Why some fields in the exported JSON file could be missed in Vantage?
JSON isn't a listing data format like CSV requiring fields always to be available even if their values are empty.
Technically and according to the generic JSON specification, fields may be missing in JSON files as they aren't declared to be required. Our JSON schema is attached to the article.
Due to specifics of the internal micro-services architecture of Vantage and different internal workers producing data, the output JSON for the same skill may be different depending on the steps a document went through during its processing life-cycle.