webfont doesn't update Less file

I have webfont set up to write Less, with this config:

webfont: {
        icons: {
            src: 'src/common/font/icons/*.svg',
            dest: 'src/common/font/output',
            options: {
                engine: 'node',
                descent: 0,
                normalize: true,
                stylesheet: 'less',
                font: 'eeIcon',
                types: 'eot,woff,ttf,svg',
                templateOptions: {
                    baseClass: 'icon',
                    classPrefix: 'icon-',
                    mixinPrefix: 'icon_'
                }
            }
        }
    }

However, I've noticed that when I add an icon and run grunt webfont, the new icon does not appear in the less. It appears in the HTML output and TTF file, but the Less doesn't get updated. If I manually delete the less file, a new Less file including the icon gets generate.

Since I'm on a Mac, I tried running sudo grunt webfont to see if it might be some weird file permissions issues, but it still won't update an existing Less document.

*Note: the fact that webfont refuses to run again if the icons and the config have not changed made this much more time consuming to debug. Is there a 'force' option?

sapegin / grunt-webfont

webfont doesn't update Less file #300