When using On Demand Migration (ODM) to migrate a Scheduled Mailbox account to the target tenant, the following error is logged:
If the Scheduling Mailbox is manually created on the target and the accounts are mapped within ODM, the following errors are logged when the migration occurs:
Note 1: Migrating an empty Scheduled Mailbox produces no errors.
Note 2: Regular user's mailbox may also contain MS Bookings items within the Calendar. Migrating such mailbox will also generate same type of errors but rest of mail items should migrate successfully.
No workaround at this time.
https://outlook.office.com/bookings/homepage
Note: Under the Accounts tab for a Scheduled Mailbox, the ODM Licensed column should show Not Required.