CiviCRM 4.1.1 Using Import to update an Alphanumeric CheckBox custom field fails to make any changes to the contact record.

In the past, if one wanted to update a contact record with an Alphanumeric CheckBox custom field, one had to export the current values, add the new values to the row and then import and UPDATE the values. This no longer works on the demo site as of yesterday. No changes of any sort to the values in the contact's alphanumeric checkBox custom field can be made. I have not tested this with other custom field types.

Steps to replicate:
1) add an alphanumeric checkBox custom field to "Constituent Information" custom field group. Create at least three values.
2) Populate a few individual contact records with different selections of the values of the new alphanumeric checkBox custom field that you created
3) export those records and select the new alphanumeric checkBox custom field that you created in the export set as well as the internal civicrm id
4) make a copy of the exported file and use it to alter the values of the exported records.
5) import the altered file using "Update"
6) export the individual contact records that you updated.
7) compare the files from step 3 and step 6

When this gets fixed, it would be better if "fill" import function added values to alphanumeric checkBox custom fields and perhaps other multivalue fields. but that's an improvement request, I guess.