.Net SDk 2.5.9 Bug: Lock error repsonse status is set to "Failure" and not "TemporaryFailure"

in CB server 4.X when requesting a locked document the IOperationResult.Status property was set to TemporaryFailre. This allowed for random backoff & re-try logic. in 5.X this status is “Failure”
This is a breaking change and feels like a bug. Was this change in behavior intentional? If so what is the prescribed way to delineate between temporary lock failures and permanent failures?