In larger environments an Azure Active Directory (AAD) synchronization can currently run for several days.
This poses a problem in that there is no corresponding property which can be used as USN for revision filtering and that many objects have to request single objects in http-request.
A single request needs about 90ms on average, but with the mass of objects run times of 3 days and more may occur.
An enhancement request (#31534) has been created.
The product team will evaluate the request and this feature may become available in a future release of the product.