A BracketByPlane PlateSystem does not have a ReferenceCollection to its symbol.
A BracketByPlane PlateSystem requires a ReferenceCollection, which provides links to the symbol information. The ReferenceCollection has relationships to the symbol inputs and other classes required to properly create the plate system and its geometry.
The display of the PlateSystem may not be correct. This problem can affect other related objects.
What You Should Do
Open the model.
In the Molded Forms task, select the BracketByPlane PlateSystem.
Verify that it has a valid symbol and modify it, if necessary. Or, select the object, and perform a re-compute 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.