Repro steps:

1. Create a new scene, create a few cubes inside. Save. Reopen the scene (important).
2. Hold down Cmd/Ctrl and try selecting objects in the Scene View (using area-select, not by simply clicking on objects)
3. Notice an Invalid Cast Exception for each object as it gets included in the selection area

Note: only happens when done in this precise order, i.e. selection has to be the next immediate action after opening the scene.

Affects Mac and Windows editors.