What is the problem?
There are conflicting statements in the spec about how platforms should handle a failed deprovisioning.
This section instructs platforms to assume the service instance to be still usable, whereas this section implies that an orphan mitigation should be performed.
Who does this affect?
Platform authors
Do you have any proposed solutions?
My gut feeling is that the orphan mitigation part was just not updated to reflect the changes done as part of PR #661. Maybe it would be enough to change the (Orphan Mitigation SHOULD be performed for Service Instances) "Yes" to "Yes if instance_usable equals false, otherwise not".