Hooks don't fire for Mutliple-value custom data sets

Steps to reproduce:

1.) Create a Custom Data set for Individuals which accepts multiple values
2.) Implement hook_civicrm_post. Trigger debugging output or logging if ($objectName == 'Individual' && $objectId && ($op =='create' || $op =='edit'))

{ //test something }

3.) In CiviCRM, click the 'Edit' link for the custom data group. Add or edit a record.

Result: Hook is not fired.