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)

expect(pageIndex).toEqual(1);
    });
    it("gets invalid page index", async function () {
      const ref = { num: 3, gen: 0 }; 
      try {
        await pdfDocument.getPageIndex(ref);
        
        expect(false).toEqual(true);
      } catch (reason) {
        expect(reason instanceof Error).toEqual(true);
      }
    });
    it("gets destinations, from /Dests dictionary", async function () {
      const destinations = await pdfDocument.getDestinations();
      expect(destinations).toEqual({
        chapter1: [{ gen: 0, num: 17 }, { name: "XYZ" }, 0, 841.89, null],
      });
    });
    it("gets a destination, from /Dests dictionary", async function () {
      const destination = await pdfDocument.getDestination("chapter1");
      expect(destination).toEqual([
        { gen: 0, num: 17 },
        { name: "XYZ" },
        0,
        841.89,
        null,
      ]);
    });
    it("gets a non-existent destination, from /Dests dictionary", async function () {
      const destination = await pdfDocument.getDestination(