Try each of the following steps in order until the issue is resolved:
  1. Globally delete the Attribute from all records or manually delete the Attribute from all records.
    Note: Be sure to save and close the record after deleting the Attribute.
  2. Open up saved batches and remove the Attribute from all Gift and Constituent records in all batches (Gift and Constituent), even if the batches have already been committed. After the Attributes are removed, either save and close the batch or purge the batch(es).