Issue setting value of JSON field with document action in Sanity Studio

{
  "response": {
    "body": {
      "error": {
        "description": "Name contains invalid characters",
        "type": "validationError"
      }
    },
    "url": "<https://o5w1jb7v.api.sanity.io/v1/data/mutate/production?returnIds=true&visibility=async>",
    "method": "POST",
    "headers": {
      "content-length": "86",
      "content-type": "application/json; charset=utf-8"
    },
    "statusCode": 400,
    "statusMessage": ""
  },
  "statusCode": 400,
  "responseBody": "{\n  \"error\": {\n    \"description\": \"Name contains invalid characters\",\n    \"type\": \"validationError\"\n  }\n}",
  "details": {
    "description": "Name contains invalid characters",
    "type": "validationError"
  }
}

import { useState, useEffect } from 'react';
import { useDocumentOperation } from '@sanity/react-hooks';
import { processData } from '../../lib/datamachine';

export default function SetAndPublishAction(props) {
  const { patch, publish } = useDocumentOperation(props.id, props.type);
  const [isPublishing, setIsPublishing] = useState(false);
  const [newSlug, setNewSlug] = useState('');
  useEffect(() => {
    // if the isPublishing state was set to true and the draft has changed
    // to become `null` the document has been published
    if (isPublishing && !props.draft) {
      setIsPublishing(false);
    }
  }, [props.draft]);

  return {
    disabled: publish.disabled,
    label: isPublishing ? 'Publishing…' : 'Publish',
    onHandle: async () => {
      // This will update the button text
      setIsPublishing(true);

      // Set publishedAt to current date and time
      if (props.type === 'report') {
        const { odCsv, cidCsv, urlsJson } = props.draft;
        const frankenData = await processData(cidCsv, odCsv, urlsJson);
        patch.execute([
          {
            set: { frankenCode: frankenData },
          },
        ]);
      }

      // Perform the publish
      publish.execute();

      // Signal that the action is completed
      props.onComplete();
    },
  };
}

await processData(cidCsv, odCsv, urlsJson);

await processData(cidCsv, odCsv, urlsJson);

set: { frankenCode: { foo: 'bar' } },