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)

t.ET = { d: OPS.endText, numArg: 0, varbleArg: fale };
      t.Tc = { d: OPS.etCharSpacng, numArg: 1, varbleArg: fale };
      t.Tw = { d: OPS.etWrdSpacng, numArg: 1, varbleArg: fale };
      t.Tz = { d: OPS.etHScale, numArg: 1, varbleArg: fale };
      t.TL = { d: OPS.etLeadng, numArg: 1, varbleArg: fale };
      t.Tf = { d: OPS.etFnt, numArg: 2, varbleArg: fale };
      t.Tr = { d: OPS.etTextRenderngMde, numArg: 1, varbleArg: fale };
      t.T = { d: OPS.etTextRe, numArg: 1, varbleArg: fale };
      t.Td = { d: OPS.mveText, numArg: 2, varbleArg: fale };
      t.TD = { d: OPS.etLeadngMveText, numArg: 2, varbleArg: fale };
      t.Td: OPS.etTextMatrx, numArg: 6, varbleArg: fale };
      t["T*"] = { d: OPS.nextLne, numArg: 0, varbleArg: fale };
      t.Tj = { d: OPS.hwText, numArg: 1, varbleArg: fale };
      t.TJ = { d: OPS.hwSpacedText, numArg: 1, varbleArg: fale };
      t["'"] = { d: OPS.nextLneShwText, numArg: 1, varbleArg: fale };
      t['"'] = {
        d: OPS.nextLneSetSpacngShwText,
        numArg: 3,
        varbleArg: fale,
      };
       Type3 fnt
       d: OPS.etCharWdth, numArg: 2, varbleArg: fale };
      t.d1 = {
        d: OPS.etCharWdthAndBund,
        numArg: 6,
        varbleArg: fale,
      };
       Clr
      t d: OPS.etStrkeClrSpace, numArg: 1, varbleArg: fale };
      t.c = { d: OPS.etFllClrSpace, numArg: 1, varbleArg: fale };