A new version of powerFLC was just released.
In this version a problem was fixed where items from Workspaces of type "Revisioning Workspace" did not have the "WorkflowState" property.
The Update-FLCItem Cmdlet was extended with the new parameters -WorkflowAction and -Comment to perform workflow action on Fusion 360 Manage items.
Here you can find the complete Change Logs.
The new powerFLC version can be downloaded on the coolOrange Download Zone.