There are other circumstances outside of the 3 reasons mentioned above that cause the move update failure. When a scenario is found as such, the registry key below can be used to reset the poison pill count and allow the move updated to process again.
* NOTE * When adding this value for a move archive failure on Step3, place the registry key on the server that houses the task where the exchange mailbox resides.
Warning: Incorrect use of the Windows registry editor may prevent the operating system from functioning properly. Great care should be taken when making changes to a Windows registry. Registry modifications should only be carried-out by persons experienced in the use of the registry editor application. It is recommended that a complete backup of the registry and workstation be made prior to making any registry changes.
Location: HKLM\Software\Wow6432Node\KVS\Enterprise Vault\Agents
DWORD: ClearFailedMoveUpdate
Value: 1
Once the poison pill count has been reset, either delete this key or disable it by setting value back to 0.
(ArchiveTask) <8180> EV:M CArchivingAgent::ProcessShortcutItem - '<Message Subject>' this is a moved item that has been poison pilled so do not try and update its metadata again