A bit more information.
The font is being managed by a sprite collection, is that relevant? The XML file looks fine, here's a snippet: It's the minus sign I really need (char id 45).
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!--Created using Glyph Designer - http://71squared.com/glyphdesigner-->
<font>
<info face="Marvin" size="260" bold="0" italic="0" charset="" unicode="0" stretchH="100" smooth="1" aa="1" padding="0,0,0,0" spacing="4,4"/>
<common lineHeight="267" base="195" scaleW="1655" scaleH="1824" pages="1" packed="0"/>
<pages>
<page id="0" file="marvin200.png"/>
</pages>
<chars count="50">
<char id="40" x="4" y="1304" width="120" height="256" xoffset="0" yoffset="-54" xadvance="120" page="0" chnl="0" letter="("/>
<char id="41" x="1474" y="1044" width="122" height="256" xoffset="0" yoffset="-54" xadvance="122" page="0" chnl="0" letter=")"/>
<char id="43" x="527" y="1304" width="112" height="114" xoffset="0" yoffset="88" xadvance="112" page="0" chnl="0" letter="+"/>
<char id="44" x="643" y="1304" width="66" height="83" xoffset="0" yoffset="119" xadvance="66" page="0" chnl="0" letter=","/>
<char id="45" x="845" y="1304" width="85" height="64" xoffset="0" yoffset="138" xadvance="85" page="0" chnl="0" letter="-"/>