Making a change to a "Mail server" or "Mail file" values inside a Person Document, is not reflected in a new run of Directory Export to a User Collection.
Exported Collection to a .tsv file should contain updated "DominoServerAddress" value.
WORKAROUND
Manually edit the incorrect "DominoServerAddress" value inside the .tsv file.
Import the .tsv file using the "Import members from TSV" option in the "Manage" part of "User Collections" part of MNE (Migrator for notes to Exchange) GUI
STATUS
This has been verified as a Defect with the ID 663457. Waiting for a fix in a future release of MNE.