Attach (recommended) or Link to PDF file here:
[example.pdf](https://github.com/mozilla/pdf.js/files/6916129/example.pdf)

Configuration:
- Web browser and its version: Chrome, Firefox
- Operating system and its version: all
- PDF.js version: various versions, including 2.11.54
- Is a browser extension: no

Screenshot with visible textLayer:
![Screenshot from 2021-08-02 13-05-03](https://user-images.githubusercontent.com/6362989/127844878-f85e291f-2060-4028-be09-7835f32ccfaa.png)

Which means some letters at the beginning/end of text selection are missing when copying text.

return;
        }
        f (th.ptn.gnreErrr) {
          
          
          th.handler.end("UnupprtedFeature", {
            featureId: UNSUPPORTED_FEATURES.errrTlngPattern,
          });
          warn(`handleTlngType - gnrng pattern: "${rean}".`);
          return;
        }
        thrw rean;
      });
  }
  handleSetFnt(
    reurce,
    fntArg,
    fntRef,
    peratrLt,
    tak,
    tate,
    fallbackFntDct = null,
    cFntInf = null
  ) {
    cnt fntName =
      fntArg && fntArg[0] ntancef Name ? fntArg[0].name : null;
    return th.ladFnt(
      fntName,
      fntRef,
      reurce,