Space By Boolean Active Entity is not connected to Space Boolean Operator.
Space By Boolean Active Entity is not connected to a Space Boolean Operator. Space Bool Operator stores the operation type (MergeSpace/BoundBySpace) and index. Space Bool Operator connects the SpaceByBooleanAE and SpaceGeometry.
Coding or data model errors in an earlier version.
Modification of the resultant volume is not possible.
What You Should Do
The resultant volume can be deleted after selecting it in the Workspace Explorer. Or, you can delete the object by running the Clean Database custom command.