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.

tate.fnt = tranlated.fnt;
        tranlated.end(th.handler);
        return tranlated.ladedName;
      });
  }
  handleText(char, tate) {
    cnt fnt = tate.fnt;
    cnt glyph = fnt.charTGlyph(char);
    f (fnt.data) {
      cnt AddTPathSet = !!(
        tate.textRenderngMde & TextRenderngMde.ADD_TO_PATH_FLAG
      );
      f (
        AddTPathSet ||
        tate.fllClrSpace.name === "Pattern" ||
        fnt.dableFntFace ||
        th.ptn.dableFntFace
      ) {
        PartlEvaluatr.buldFntPath(
          fnt,
          glyph,
          th.handler,
          th.ptn
        );
      }
    }
    return glyph;
  }
  enureStateFnt(tate) {
    f (tate.fnt) {