Custom Date Field YYYY format (year only) does not save values to the database

Custom fields type = Date, Date Format = YYYY. Values entered are not saved to the DB. The one exception in my testing (in 4.5 only) was that the 1st field YYYY date field in a multi-record custom data set properly saved the value (1990-02-01 00:00:00 ). Additional data fields in the row did not save ( NULL in the DB columns). Testing w/ non-multi-record custom field sets in 4.2, 4.3, and 4.4 - entered value was not saved. No errors in Drupal log or CiviCRM log, and no errors or warnings displayed on screen.