CustomFieldsOnUpdate, Issues with RT3.6?

Team RT–

We are heavy users of the CallBack-based solution often used to allow
Custom Field updates within Update.html. Refer to the BP Wiki for the
solution I refer to:

It appears that since upgrading to RT 3.6 (this past weekend), this
functionality has become slightly less operational. For example:

  • If one clicks Reply and changes CFs, they take. However,
  • If one clicks Reply, changes CFs and includes text to be Reply’d with,
    the email goes out but the CF changes don’t take

Does anyone know what modifications are necessary for RT 3.6 to make this
CallBack-based solution work properly? Is there a better way?