API in 4.4.4 does not return custom fields unless the request filters by those fields

Perform this query:
civicrm_api('Contact', 'get', Array('version'=>'3', 'return' => 'custom_2', 'id'=>1));

Receive this result:
Array
(
[is_error] => 0
[version] => 3
[count] => 1
[id] => 1
[values] => Array
(
[1] => Array
(
[contact_id] => 1
[id] => 1
)

)

)

Notice that the custom_2 field is not returned.

However, this call:
civicrm_api('Contact', 'get', Array('version'=>'3', 'return' => 'custom_2', 'custom_2' => 'Committed', 'id'=>1));

Returns this:
Array
(
[is_error] => 0
[version] => 3
[count] => 1
[id] => 1
[values] => Array
(
[1] => Array
(
[contact_id] => 1
[civicrm_value_custom_contact_fields_1_id] => 2548
[custom_2] => Committed
[id] => 1
)

)

)

Notice that the custom field is properly returned.