This value represents the time at which the network element (NE) was formally de-enrolled from EMS management, using the NortelNMItimeStampDef textual convention. An admin receiving a de-enrollment notification uses this timestamp to know precisely when a device stopped being managed, useful for auditing management-domain changes. For example, this timestamp would let an admin confirm an NE was deliberately removed from management at a specific time rather than simply becoming unreachable.