Users in UCS@school are synced to azure, but no license/plan is assigned to the users.
In school environments the concept of license plans and profiles are used as decribed here:
Check if a profile is stored
→ UMC Groups → Domain-Users → office 365 tab, or an other group you have previously defined for the license. teacher- or student-
You have to define the profiles and then trigger the listener.module again.
univention-directory-listener-ctrl resync office365-user
or you have to unset and reset the UniventionOffice365Enabled attribute.