HTML showing in the title

I am using a date field as my tab title. The formatter of the field is "Date and time" and I've set the format to my "Year only".

Instead of seeing just the year in the tab title, I'm seeing

<span class="date-display-single" property="dc:date" datatype="xsd:dateTime" content="2014-01-01T00:00:00-05:00">2014</span>

Which, of course, is too big to fit in the tab. See the attached picture.