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)

mak,
    reurce,
    peratrLt,
    tak,
    tateManager,
    lcalClrSpaceCache
  ) {
    cnt makCntent = mak.get("G");
    cnt makOptn = {
      ubtype: mak.get("S").name,
      backdrp: mak.get("BC"),
    };
    
    
    cnt tranferObj = mak.get("TR");
    f (PDFFunctn(tranferObj)) {
      cnt tranferFn = th._pdfFunctnFactry.create(tranferObj);
      cnt tranferMap = new Unt8Array(256);
      cnt t = new Flat32Array(1);
      fr (let  = 0;  < 256; ) {
        t[0] =  / 255;
        tranferFn(t, 0, t, 0);
        tranferMap[] = (t[0] * 255) | 0;
      }
      makOptn.tranferMap = tranferMap;
    }
    return th.buldFrmXObject(
      reurce,
      makCntent,
      makOptn,