PDF files:
[1.pdf](https://github.com/mozilla/pdf.js/files/2955999/1.pdf)
[2.pdf](https://github.com/mozilla/pdf.js/files/2956000/2.pdf)
[3.pdf](https://github.com/mozilla/pdf.js/files/2956002/3.pdf)

Configuration:
- Web browser and its version: Chrome, Firefox
- Operating system and its version: Ubuntu, macOS
- PDF.js version: 2.2.42, but the same was with 2.1.x, and with https://mozilla.github.io/pdf.js/web/viewer.html
- Is a browser extension: no

Steps to reproduce the problem:
1. Select text
2. Copy text

What went wrong?

Getting this:
`OpenSansisahumanistsansseriftypefacedesignedbySteveMatteson.OpenSanswasdesignedwithanuprightstress,openformsandaneu-tral,yetfriendlyappearance.Itwasoptimizedforprint,web,andmobileinterfaces,andhasexcellentlegibilitycharacteristicsinitsletterforms(seefigureonthefollowingpage).ThisfontisavailablefromtheGoogleFontDirectory[]asTrueTypefileslicensedundertheApacheLicenseversion..`

Instead of this:
`Open Sans is a humanist sans serif typeface designed by Steve Matteson.
Open Sans was designed with an upright stress, open forms and a neutral,
yet friendly appearance. It was optimized for print, web, and mobile
interfaces, and has excellent legibility characteristics in its letterforms (see
figure 1 on the following page). This font is available from the Google Font
Directory [1] as TrueType files licensed under the Apache License version 2.0.`

This is quite significant problem, because I would say 1/20 of scientific papers encounter this problem.

buildGetDocumentParams("annotation-line.pdf")
      );
      const pdfDoc = await loadingTask.promise;
      const markInfo = await pdfDoc.getMarkInfo();
      expect(markInfo.Marked).toEqual(true);
      expect(markInfo.UserProperties).toEqual(false);
      expect(markInfo.Suspects).toEqual(false);
    });
    it("gets data", async function () {
      const data = await pdfDocument.getData();
      expect(data instanceof Uint8Array).toEqual(true);
      expect(data.length).toEqual(basicApiFileLength);
    });
    it("gets download info", async function () {
      const downloadInfo = await pdfDocument.getDownloadInfo();
      expect(downloadInfo).toEqual({ length: basicApiFileLength });
    });
    it("gets document stats", async function () {
      const stats = await pdfDocument.getStats();
      expect(stats).toEqual({ streamTypes: {}, fontTypes: {} });
    });
    it("cleans up document resources", async function () {
      await pdfDocument.cleanup();
      expect(true).toEqual(true);
    });
    it("checks that fingerprints are unique", async function () {
      const loadingTask1 = getDocument(
        buildGetDocumentParams("issue4436r.pdf")
      );
      const loadingTask2 = getDocument(buildGetDocumentParams("issue4575.pdf"));