Bates Numbers not adding, which PDF type allow bates numbers

We're having an issue adding bates numbers to documents. I believe it's because of the type of PDF it is. Is there a way to tell if that is the issue? And which type of PDF will allow bates numbers.

Steps to recreate issue

1. Receive 26 PDF files from client

2. Open Acrobat Pro XI 11.0.14

3. Tools -> Text Recognition -> OCR all 26 PDFs replacing originals

     3a. Open a few files to confirm OCR'd

4. Tools -> Pages -> Bates Numbering all 26 PDfs replacing originals, receive message saying complete.

- ERROR: open files, Bates Numbering now showing up.