custom file upload fields broken in backend

this seems to be the same issue reported as fixed here:
https://issues.civicrm.org/jira/browse/CRM-17770

however – testing in 4.7.3 in Joomla and Drupal (haven't tested WP yet) it is still broken.

to reproduce –

• create a custom field set in a tab
• create a custom field of type file
• add the field to a profile
• visit the profile and upload a file
• visit the contact in the admin side and click the custom data tab

it errors with "one of parameters (value:...) is not of the type Integer.

see: http://dmaster.demo.civicrm.org/civicrm/contact/view?reset=1&cid=202

this renders the entire custom data set completely unavailable. I would view as a pretty critical issue as anyone with existing custom file data will not be able to access the record via the admin side.