PDF received via http.postFormData missing images

When I use Postman, I have no trouble sending a PDF to my API for processing, but when I use http.postFormData('myapi.no', { headers: { 'A-Header': 'thestuff' }, formData: { map: JSON.stringify({ "file": ["variables.file"] }), file: { buffer: Buffer.from(downloadRes.data, 'binary'), filename: 'annot.pdf', contentType: 'multipart/form-data' } } })
, the image of the PDF is missing.


Are the boundaries correct?