When a data source has been added to a case and indexing is complete, the node that was used to index does not automatically "release" itself or make itself available for any other processing. Also, the Admin cannot share the case as the Node has it "locked".
The intended workflow is to click the "Close Case" button to (1) release the node for processing and (2) release the case for sharing.
The term "Close Case" typically means we’re finished from the standpoint of legal involvement and we’re free to delete the project from the system; the matter is adjudicated, a settlement was reached, we fired the guy, and like that.
Suggest renaming this button to something like "Release Node" or "Finished" - or, assuming there aren't other programmatic reasons to keep it connected, just *automatically* release the node when indexing is complete without requiring user inputs.