System.Data.SqlClient.SqlException: Cannot insert the value NULL into column 'ALIAS' INSERT fails (4315428)

When using LDAP filters to manage user membership within mailbox collections, after updating the intended Active Directory attribute to move a user or users into their new collection, they are never displayed within the statistics section of the new collection. 

However when previewing the user membership of the source and destination collections, they appear correctly.  As well, when reviewing the Migration Agent for Exchange logs it will appear that the users are still being processed by the agent handling the collection they were intended to be moved from.

The following error will also be present within the Migration Agent for Exchange log for the collection the users were being moved from:

Error    System.Data.SqlClient.SqlException: Cannot insert the value NULL into column 'ALIAS', table 'DATABASENAME.dbo.MAILBOX'; column does not allow nulls. INSERT fails.