Out of bounds Crash when adding item to Scene

There is a crash related to the new timeline.  When adding new items to the scene under certain conditions the timeline will read past the bounds of an array and crash when trying to add the new item to the timeline model.

To reproduce the issue use the attached test scene.  Open In 3D Studio and open the master slide editor.  Drag a Group Item into the scene view.  When you release the item it will try and create it and update the timeline model, and that will lead to a crash.