Document AI Training Errors - JSON and Schema not in agreement

[Steve2023]

Hello,

I'm a novice user in the Document.AI world and while attempting to train a processor I've encountered the "Training stopped due to errors" message. When I investigate this error I observe sections of the JSON similar to:

              "@type": "type.googleapis.com/google.rpc.ErrorInfo",
              "reason": "INVALID_DOCUMENT",
              "domain": "documentai.googleapis.com",
              "metadata": {
                "num_fields": "0",
                "annotation_name": "union",
                "num_fields_needed": "1",
                "field_name": "entities.text_anchor.text_segments",
                "document": "b2c7cb53fbb0bd58.json"
              }

The field union is set in the schema as "optional once" and so the metadata's report that 0 are found and 1 required seems off.

I understand there is a UI bug currently being investigated regarding these text_segments errors but it's unclear if I can work around this. I've been at a standstill for a week now, and shy of only identifying a single field per image it's not obvious to me what I'm doing on these particular records that is causing the error to appear.

Some of my identified fields overlap, which someone suggested could be the cause, however, the handwriting does overflow the typical fields and sometimes overlaps, so guidance would be appreciated.

Thanks!