
Attach (recommended) or Link to PDF file here:
[NAPEN16171380959.pdf](https://github.com/mozilla/pdf.js/files/6143802/NAPEN16171380959.pdf)

Configuration:
- Web browser and its version: Firefox 88 Nightly
- Operating system and its version: Windows 10
- PDF.js version:
- Is a browser extension: No

What went wrong? (add screenshot)
![](https://user-media-prod-cdn.itsre-sumo.mozilla.net/uploads/images/2021-03-15-10-58-27-ce2796.png)


for (var charCode in charCodeToGlyphId) {
          if (glyphId === charCodeToGlyphId[charCode]) {
            return charCode | 0;
          }
        }
        newMapping.charCodeToGlyphId[
          newMapping.nextAvailableFontCharCode
        ] = glyphId;
        return newMapping.nextAvailableFontCharCode++;
      }
      var seacs = font.seacs;
      if (SEAC_ANALYSIS_ENABLED && seacs && seacs.length) {
        var matrix = properties.fontMatrix || FONT_IDENTITY_MATRIX;
        var charset = font.getCharset();
        var seacMap = Object.create(null);
        for (var glyphId in seacs) {
          glyphId |= 0;
          var seac = seacs[glyphId];
          var baseGlyphName = StandardEncoding[seac[2]];
          var accentGlyphName = StandardEncoding[seac[3]];
          var baseGlyphId = charset.indexOf(baseGlyphName);
          var accentGlyphId = charset.indexOf(accentGlyphName);
          if (baseGlyphId < 0 || accentGlyphId < 0) {
            continue;
          }