As others have commented, this is expected.
Refer to Passbook Programming Guide: Updating a Pass specifically -
The device library identifier is a Passbook-specific shared secret between the user’s device and your web server. It is not related to the device identifier (UDID). The device identifies itself with a different ID to different servers and it may change its ID at any time. Its purpose is to allow efficient communication between the device and your server, not to let your server keep a list of of what passes are currently installed on a device. The device library identifier uniquely identifies a device and indicates that the entity making the request is authorized to make such a request.
and also from Local and Push Notitifcation Programming Guide
Note: A device token is not the same thing as the device UDID returned by the identifierForVendor or uniqueIdentifier property of UIDevice or any other similar properties such as the advertisingIdentifier property of ASIdentifierManager.
Apple goes to some lengths to prevent the facilitation of unintentional tracking, so different frameworks will return different device identifiers on the same device for a given App. Different Apps on the same device will also obtain different identifiers from the same frameworks.
EDIT - The Pushtoken (also supplied at registration) is used to identify the device in subsequent push notifications, not the DeviceLibraryID, but the concept is the same - this identifier is unique to other identifiers on the same device.