This is a limitation in the product when scheduling a migration via MfNE to O365 with the Admin Pool enabled.
In order to make this work, Windows scheduler has to be used as per the following steps:
1.- Create the scheduled task like normal in MFNE.
2.- Then add a windows scheduled task to run QSched.exe (in the MNE installation directory), at the same time you are doing this, you have to set option "Run only when user is logged on".
Note: Obviously the user has to be logged on at the time the task is to run.
3.- Disable "Notes Migrator for Exchange Task Scheduler" service when using this method.
This will be documented on v4.12.