parsley.js 'fails' when trying to validate checkbox

We are re-designing a site and part of that re-design involves making the site accessible to screen readers and the like. I'm using latest version (2.8.0). Here's what's happening --- validation for all text, select and textarea fields in our forms work perfectly. In order to be accessible, checkbox and radio inputs are wrapped in tags. The html for a set of checkboxes looks like this:

<div class="form-group">
    <p id="applicant_type_desc" style="margin-bottom: 6px;"><strong>I am: <span class="text-danger" aria-hidden="true">*</span><span class="sr-only">Required</span></strong> <em class="small">(check all that apply)</em></p>
    <div class="checkbox">
        <label id="applicant_type_patient_desc">
            <input type="hidden" name="applicant_type_patient" id="" value="N">
            <input type="checkbox" name="applicant_type_patient" id="applicant_type_patient" value="Y" {checked_applicant_type_patient} aria-labelledby="applicant_type_desc applicant_type_patient_desc" data-parsley-multiple="type" data-parsley-error-message="Please specify whether you are a patient, relative, employee or other."> 
            A patient
        </label>
    </div>

followed by more checkbox divs without error messages and ended with an end div for the for form-group wrapper.

If I load the form and click 'submit', all the text fields are validated properly. If I add 'required' to the checkbox above, when 'submit' is clicked nothing happens and the form is submitted with no validation at all.

The same thing happens when I try to validate a radio button set as required.

There is some custom jQuery and parsley code which creates a div to hold all the error messages and transforms the error messages into links to the field id so that a screen reader can follow them and focus on the field in error. But imho, this should have no effect on why the form validation doesn't kick in.

I'm absolutely baffled.

FYI - I tried this using an earlier version (2.0.3) of parsley and the validation actually worked, although all my custom error processing was ignored.

Any insight would be greatly appreciated.