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.

}
      delete tables.glyf;
      delete tables.loca;
      delete tables.fpgm;
      delete tables.prep;
      delete tables["cvt "];
      this.isOpenType = true;
    } else {
      if (!tables.loca) {
        throw new FormatError('Required "loca" table is not found');
      }
      if (!tables.glyf) {
        warn('Required "glyf" table is not found -- trying to recover.');
        
        tables.glyf = {
          tag: "glyf",
          data: new Uint8Array(0),
        };
      }
      this.isOpenType = false;
    }
    if (!tables.maxp) {
      throw new FormatError('Required "maxp" table is not found');
    }
    font.pos = (font.start || 0) + tables.maxp.offset;
    const version = font.getInt32();
    const numGlyphs = font.getUint16();
    if (
      properties.scaleFactors &&
      properties.scaleFactors.length === numGlyphs &&