Date problem in profile edit Custom date field

When a custom date field is used in a profile and the profile is edited, the existing date is not shown.

The current code in js/Common.js updateInputFields() sets the datepicker date as follows:

$dateField.datepicker('setDate', _.includes(val, '-') ? $.datepicker.parseDate('yy-mm-dd', val) : null);

When editing the field at the CiviCRM contact screen, val is set as eg 2017-02-28 00:00:00 and it works OK. However when used in a profile edit, the field looks like 02/28/2017 and so doesn't work.

CRM\Utils\Date.php :: setDateDefaults() deliberately sets the $dateFormat = 'm/d/Y';

I repeated the problem at a demo site: creating a new field and profile, then creating a new user and editing the field at the contact screen and by editing the profile, ie today:

https://demo.circle-interactive.co.uk/civicrm/contact/view?reset=1&cid=214

https://demo.circle-interactive.co.uk/civicrm/profile/edit?reset=1&gid=14&id=214