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.

case "TrueType":
        case "CIDFontType2":
          this.mimetype = "font/opentype";
          
          
          data = this.checkAndRepair(name, file, properties);
          if (this.isOpenType) {
            adjustWidths(properties);
            type = "OpenType";
          }
          break;
        default:
          throw new FormatError(`Font ${type} is not supported`);
      }
    } catch (e) {
      warn(e);
      this.fallbackToSystemFont(properties);
      return;
    }
    amendFallbackToUnicode(properties);
    this.data = data;
    this.fontType = getFontType(type, subtype, properties.isStandardFont);
    
    this.fontMatrix = properties.fontMatrix;
    this.widths = properties.widths;
    this.defaultWidth = properties.defaultWidth;
    this.toUnicode = properties.toUnicode;
    this.seacMap = properties.seacMap;
  }
  get renderer() {