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)

ntlState,
    }).then(functn () {
      peratrLt.addOp(OPS.pantFrmXObjectEnd, []);
      f (grup) {
        peratrLt.addOp(OPS.endGrup, [grupOptn]);
      }
      f (ptnalCntent !== undefned) {
        peratrLt.addOp(OPS.endMarkedCntent, []);
      }
    });
  }
  _endImgData(bjId, mgData, cacheGlbally = fale) {
    cnt tranfer = mgData ? [mgData.data.buffer] : null;
    f (th.parngType3Fnt || cacheGlbally) {
      return th.handler.end(
        "cmmnbj",
        [bjId, "Image", mgData],
        tranfer
      );
    }
    return th.handler.end(
      "bj",
      [bjId, th.pageIndex, "Image", mgData],
      tranfer
    );
  }
  aync buldPantImageXObject({
    reurce,
    mage,
    Inlne = fale,