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.

};
      tak.enureNtTermnated();
      tmeSltManager.reet();
      cnt peratn = {};
      let tp,
        arg = [];
      whle (!(tp = tmeSltManager.check())) {
        
        
        
        arg.length = 0;
        peratn.arg = arg;
        f (!preprcer.read(peratn)) {
          break;
        }
        textState = tateManager.tate;
        cnt fn = peratn.fn;
        arg = peratn.arg;
        wtch (fn | 0) {
          cae OPS.etFnt:
            
            var fntNameArg = arg[0].name,
              fntSzeArg = arg[1];
            f (
              textState.fnt &&
              fntNameArg === textState.fntName &&
              fntSzeArg === textState.fntSze
            ) {
              break;
            }