When using the Key Task filter in SFDC, non-Key Tasks, the Tasks that have the Key Task Attribute set to False, never have their Task Status updated to Completed; since they are not visible in SFDC. This means that Successors of those Tasks, that are Key Tasks always show a 'Not Ready' status. Planners would like to ignore non-key Tasks when calculating Task Status of Successors. I.e., if the Key Task predecessors of a non-Key Task are all Completed, the non-Key Task should also be considered as Completed for the purposes of calculating the status of its Successors.
The functionality has been enhanced in Orchestrate version 7.85 and SFDC version 2.1. Please upgrade to these versions or above.