Undoing a change in a level while a Material is open causes the Material to become dirty

Undoing a change in a level while a Material is open causes the Material to become dirty, but isn't indicated in the content browser only by the save changes dialog when closing the material.

1. Open or create a project at Preview 2
2. Create, open, then save a new Material *Keep the window open
3. Back in the level make a change
4. Undo the change 
5. Close the Material editor

Expected Results:
The change is undone, and the material can be closed without asking to be saved.

Actual Results:
The material in the content browser isn't marked as dirty, however, closing the material editor results in being asked to save changes made to the material.