In certain circumstances when an exchange mailboxes are re enabled for archiving it get 'DefaultVaultId' from ‘ExchangeMailboxEntry’ table of directory database. A duplicate archive may get create if 'DefaultVaultId' is blank at the time when mail-box is re-enabled. Below SQL queries are helpful for Administrator if they need duplicate archive details to know the scope of issue if this is happen in larger scale.
Get count of each duplicate archive have environment:-
SELECT ArchiveName, ArchiveDescription, COUNT(*) AS CountOf
WHERE Type <> 129
GROUP BY ArchiveName, ArchiveDescription
HAVING COUNT(*) > 1
Get Archive Name, Archive description, ArchiveID with associated Vault Store & Storage server.