A CreatePlatePartAE does not have a related plane.
A create plate part active entity (AE) does not have a related plane: Missing the StructGeometryHasPorts relationship to IJStructGeometry (various) for StructPort_AE.
You cannot manipulate the object itself or other objects related to it.
What You Should Do
Open the model.
In the Molded Forms task, modify the object by selecting a plane, and click Finish. Or, select the object, and perform a re-computation to update it.
Re-run the Check Database Integrity custom command and the DBIntegrity report.
If the object is still posted, contact Smart 3D Support.