wrong thumbnail when uploading product video media via graphql

[Joseph_Chan]

I'm uploading video media via shopify graphql product api but the thumbnails are wrong (showing thumbnails of other videos). But after clicking play the correct video plays. I've tried setting the media thumbnail to null and empty string but that doesn't work also.

const generateStagedUploads = (productId, sourceURL, mediaType) => {
  return `
    mutation createProductMedia {
  productCreateMedia(productId: "${productId}", media: [
    {
      originalSource: "${sourceURL}",
      alt: "${productId}",
      mediaContentType: ${mediaType}
    }
  ]) {
    media {
      ... fieldsForMediaTypes
      mediaErrors {
        code
        details
        message
      }
    }
    product {
      id
    }
    mediaUserErrors {
      code
      field
      message
    }
  }
}
fragment fieldsForMediaTypes on Media {
  alt
  mediaContentType
  preview {
    image {
      id
    }
  }
  status
  ... on Video {
    id
    sources {
      format
      height
      mimeType
      url
      width
    }
  }
}
    `
}

const generateStagedUploadsVideoMuation = ({ video_name, video_size }) => {
  return `
mutation generateStagedUploads {
  stagedUploadsCreate(input: [
    {
      filename: "${video_name}",
      mimeType: "video/mp4",
      resource: VIDEO,
      fileSize: "${video_size}"
    },
  ])
    {
    stagedTargets {
      url
      resourceUrl
      parameters {
        name
        value
      }
    }
    userErrors {
      field, message
    }
  }
}
  `
}

exports.set_media_thumbnail_to_empty_string = async (product_id, media_id, first_image_url) => {
  await client.query({
  data: {
    "query": `mutation productUpdateMedia($media: [UpdateMediaInput!]!, $productId: ID!) {
      productUpdateMedia(media: $media, productId: $productId) {
        media {
          alt
        }
      }
    }`,
    "variables": {
      "productId": product_id,
      "media": [
        {
          "previewImageSource": first_image_url,
          "id": media_id
        },
      ]
    },
  },
  })
}