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(defaultAnnotations[0].url).toBeUndefined();
      expect(defaultAnnotations[0].unsafeUrl).toEqual(
        "../../0021/002156/215675E.pdf#15"
      );
      expect(docBaseUrlAnnotations[0].url).toEqual(
        "http://www.example.com/0021/002156/215675E.pdf#15"
      );
      expect(docBaseUrlAnnotations[0].unsafeUrl).toEqual(
        "../../0021/002156/215675E.pdf#15"
      );
      expect(invalidDocBaseUrlAnnotations[0].url).toBeUndefined();
      expect(invalidDocBaseUrlAnnotations[0].unsafeUrl).toEqual(
        "../../0021/002156/215675E.pdf#15"
      );
      await Promise.all([
        defaultLoadingTask.destroy(),
        docBaseUrlLoadingTask.destroy(),
        invalidDocBaseUrlLoadingTask.destroy(),
      ]);
    });
    it("gets text content", async function () {
      const defaultPromise = page.getTextContent();
      const parametersPromise = page.getTextContent({
        normalizeWhitespace: true,
        disableCombineTextItems: true,
      });
      const data = await Promise.all([defaultPromise, parametersPromise]);
      expect(!!data[0].items).toEqual(true);
      expect(data[0].items.length).toEqual(12);