DB Error When Changing Order of Fields Within Custom Data Group

On attempting to move a field to the bottom of a custom data group at http://www.example.com/civicrm/admin/custom/group/field, I received the error below, and the page content was overwritten by the message "This should never been seen."

Database Error Code: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1, 1064
Additional Details:

Array
(
[callback] => Array
(
[0] => CRM_Core_Error
[1] => handle
)

[code] => -2
[message] => DB Error: syntax error
[mode] => 16
[debug_info] => UPDATE civicrm_custom_field SET weight = weight - 1 WHERE id != 4 AND weight > 1 AND custom_group_id = [nativecode=1064 ** You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1]
[type] => DB_Error
[user_info] => UPDATE civicrm_custom_field SET weight = weight - 1 WHERE id != 4 AND weight > 1 AND custom_group_id = [nativecode=1064 ** You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1]
[to_string] => [db_error: message="DB Error: syntax error" code=-2 mode=callback callback=CRM_Core_Error::handle prefix="" info="UPDATE civicrm_custom_field SET weight = weight - 1 WHERE id != 4 AND weight > 1 AND custom_group_id = [nativecode=1064 ** You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near '' at line 1]"]
)