Steps to reproduce the issue

• I'm using subform for my module parameters
• I have this code on my xml :

<field name="items" type="subform" formsource="modules/mod_modulex/fields/item.xml" min="1" max="4" multiple="true" layout="joomla.form.field.subform.repeatable-table" groupByFieldset="true" label="Subform Field" description="Subform Field Description" />

• This is the content of the item.xml

<?xml version="1.0" encoding="UTF-8"?>
<form>
<fieldset name="items_fieldset" label="Fields">
    <field
            name="field_label"
            type="text"
            label="Text"
            size="40" />
        <field name="field_is_required"
            type="radio"
            default="1"
            label="Required" class="btn-group btn-group-yesno">
                <option value="0">JNO</option>
                <option value="1">JYES</option>
            </field>
</fieldset>
</form>

Expected result

The button group yes-no styling works properly

Actual result

The button group yes-no styling working with the first item only. Sometimes it's working properly until the 5th child items

System information (as much as possible)

Joomla 3.6.2

Additional comments