input type checkbox generating value attribute twice

[levinse]

The checkbox input type appears to be generating the value attribute in the HTML twice. Once with the value set in my form template and again with an empty value for the value attribute.

For example, given:
<input type="checkbox" name="certification1" id="certification1" regex="^[A-Za-z0-9,\. ]+$" value="whatever blah blah" required />
the output is:
<input id="certification1" pattern="^[A-Za-z0-9,\. ]+$" value="whatever blah blah" required="required" type="checkbox" name="certification1" value="" />