PDF Extract API inconsistent response when using VBA

We are observing a peculiar problem with Adobe PDF Extract API 

When submitting API request (POST) via postman to https://cpf-ue1.adobe.io/ops/:create we get full response, which contains 4 files (csv, png, x json files), see response_postman attached. Jsonoutput in this case contains elements array with extracted data

When exactly the same request is submitted using VBA (using xmlhttprequest) with the same request parameters and headers, we get a response with Status 200, but only 2 JSON files (PNG and CSV are missing) see the second file. Furthermore, the elements array is blank.

Both requests were sent 1 minute apart

postman - 20/09/2021 11:04
xmlhttprequest - 20/09/2021 11:05.