QMM for AD, passwords do not synchronize from destination to source, only from source to destination?

Any idea why this happens? I have two domains, one source and destination, the synchronization of passwords in both directions was working, we even started the migration process and it is not possible to synchronize keys from destination to source. We have Office 365 and an AD Connect in the origin, that's why we need the synchronization in both directions to work. The configuration of passwords at GPO level in both domains is the same.