Summary hidden if Text field has Unlimited number of values

When you create a Field Type of Text (formatted, long, with summary) you get an option to check for Summary Input which allows you to have a field to explicitly set a Summary. This field is only visible, however, if the Allowed number of values in Field settings is Limited to 1.

Using the 'Unlimited' option or defining values greater than 1 causes the form to auto-hide the Summary field and label. The markup is there, but inline css on the element is setting the display to none.

<div class="js-text-summary-wrapper text-summary-wrapper" style="display: none;">
    ...
 </div>