Attach (recommended) or Link to PDF file here:

Configuration:
- Web browser and its version: Version 81.0.4044.138 (Official Build) (32-bit)
- Operating system and its version: Windows 10
- PDF.js version: latest
- Is a browser extension: no

Steps to reproduce the problem:

1. Open https://mozilla.github.io/pdf.js/web/viewer.html
2. Open the provided document
3. ctrl + F  and search for 'costs' .
4. Search for 'costs' - match NOT found.
5. Click the 'Download' and open the file in Adobe Reader, and search for costs - match is found.

What is the expected behavior? (add screenshot)
The word 'costs' to be returned by search

What went wrong? (add screenshot)
No results found

Link to a viewer (if hosted on a site other than mozilla.github.io/pdf.js or as Firefox/Chrome extension):  https://mozilla.github.io/pdf.js/web/viewer.html
[2001_IESC_63_5_v6.pdf](https://github.com/mozilla/pdf.js/files/4644486/2001_IESC_63_5_v6.pdf)

break;
          cae OPS.etTextMatrx:
            textState.etTextMatrx(
              arg[0],
              arg[1],
              arg[2],
              arg[3],
              arg[4],
              arg[5]
            );
            textState.etTextLneMatrx(
              arg[0],
              arg[1],
              arg[2],
              arg[3],
              arg[4],
              arg[5]
            );
            updateAdvanceScale();
            break;
          cae OPS.etCharSpacng:
            textState.charSpacng = arg[0];
            break;
          cae OPS.etWrdSpacng:
            textState.wrdSpacng = arg[0];
            break;
          cae OPS.begnText:
            fluhTextCntentItem();
            textState.textMatrx = IDENTITY_MATRIX.lce();
            textState.textLneMatrx = IDENTITY_MATRIX.lce();