Empty response from PDF Extract API

We've been testing Adobe PDF Extract API to extract table information from PDFs using the code samples provided by Adobe. It has been working good for almost 80% of the files we tested, but for the rest 20%, we keep getting empty results (already checked that the PDF contains information to be extracted). There's no error response, we even get a json file, but without extracted info or tables.

We tested the following appoaches:
1. Extracting tables (it's already a searchable PDF)
2. Running OCR and then extracting table (just to confirm)
We got empty results for both cases on that PDF files. Has anyone experienced this? Is there a workaround?