After migrating mailbox content from Domino into the Exchange server, certain permissions might be set to 'NONE' on the corresponding folders in the Exchange mailbox and the log displays a warning:
14:11:55 WARNING: [4684-33-58-00000000] Downgraded folder '~CALENDAR' Acl rights for '"Username" email@example.com' to 'None'.
14:11:55 Mismatch between Notes and Exchange Acl rights
Since Notes Migrator for Exchange (NME) version 4.4.2.X, Notes folder ACL's which do not have an exact match in Exchange are downgraded to a lower level.
For example: When a user has an ACL permission of 'Read Public Documents' in Domino, NME will not be able to find a corresponding ACL permission in Exchange and will therefore downgrade the users permission to 'NONE'.
This is by design.