Load Class Diagram Error (conversion from double to cell is not possible)

I am trying to open a Class Diagram I saved in the Class Diagram Viewer previously, and it fails to open the file. I get the following:

>> h = matlab.diagram.ClassViewer;
>> h.load('class_diagram_file.mldatx')
Conversion to double from cell is not possible.

Error in classdiagram.app.core.ClassDiagramApp/loadFromFactoryImpl

Error in classdiagram.app.core.ClassDiagramApp>@(ops)self.loadFromFactoryImpl(factory)

Error in classdiagram.app.core.ClassDiagramApp/loadFromFactory

Error in classdiagram.app.io.IOMgr/loadFrom

Error in classdiagram.app.core.ClassDiagramApp/loadDiagram

Error in matlab.diagram.ClassViewer/load

When this happens, the ClassViewer dialog box appears, but is empty. I cannot recover the file I previously saved.