I have a UNIFYBroker/Plus link with outgoing deprovision configured to a CSV adapter/connector, and when a joined locker entity is deleted the joined adapter/connector entity isn't deleted when a Changes Sync is run on the link. It isn't deleted when a Baseline Sync runs on the link, either.
I tried the same process with a PowerShell connector and the same behaviour was apparent (i.e. the adapter/connector entity was not deleted). I added logging and confirmed that the entity was not passed to the PowerShell connector's Delete script at all.
For reference, after Sync the Remove Joins page for the link did not show the deleted entity for either the locker or the adapter.
I don't know of anyone from Professional Services who has used Outgoing Deprovision in a UNIFYBroker/Plus solution before, so it may be worth checking around to see if this functionality has every been exercised before.
Customer support service by UserEcho