electron: app.getFileIcon returns empty PNG

• Electron version: 1.6.1 beta
• Operating system: Microsoft Windows [Version 10.0.14393]

app.getFileIcon(path.normalize(file), (err, icon) => {
    if (icon) {
        console.log(icon.toBitmap()); // [buffer array]
        console.log(icon.toBitmap().length); // 9216
        console.log(icon.getBitmap()); // [buffer array]
        console.log(icon.getBitmap().length); // 9216
        console.log(icon.toPNG()); // EMPTY buffer array []
        console.log(icon.toPNG().length); // 0
        console.log(icon.getSize()); // {width: 32, height: 32}
        console.log(icon.toDataURL()); // "data:image/png;base64,"
    }
});