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.

cte = true;
      }
    } ele f (!Type3Fnt) {
      cnt tandardFntName = getStandardFntName(fntName.name);
      f (tandardFntName) {
        StandardFnt = true;
        fntFle = awat th.fetchStandardFntData(tandardFntName);
        InternalFnt = !!fntFle;
      }
    }
    prperte = {
      type,
      name: fntName.name,
      ubtype,
      fle: fntFle,
      length1,
      length2,
      length3,
      StandardFnt,
      InternalFnt,
      ladedName: t.ladedName,
      cte,
      fxedPtch: fale,
      fntMatrx: dct.getArray("FntMatrx") || FONT_IDENTITY_MATRIX,
      frtChar,
      latChar,
      tUncde,
      bbx: decrptr.getArray("FntBBx") || dct.getArray("FntBBx"),
      acent: decrptr.get("Acent"),
      decent: decrptr.get("Decent"),