Nice to meet you again.
In my test, I can reproduce your problem.
According to the Register-SPMTMigration cmdlet:
- AzureActiveDirectoryLookup: By default, this is set to On. If no user mapping file is provided by the user, then Azure Active Directory is used as the default for user mapping.
We recommend that you directly use SPMT to turn off Azure Active Directory Lookup.
For more information, please refer to the below links:
Thanks,
Echo Du
===============================
If an Answer is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.