To reproduce:

1. Open the project, attached by user (New Unity Project 32.zip)
2. Open Timeline
3. Select "GameObject" in the hierarchy
4. Add Animation Track in the Timeline
5. Drag "Blueisland" game object into the animator slot
6. Press Record (red circle on the Animation Track)
7. Select "Blueisland" game object in the Hierarchy
8. Expand any material on the object and change Tiling X parameter
9. Observe console

Expected: changing Tiling property of the material should add a key in the Timeline and throw no errors
Actual: no key is added and "NullReferenceException: Object reference not set to an instance of an object" error is thrown if Tiling property is changed on the material while recording in the Timeline

Reproduced in 2017.1.0b1, 2017.1.0b2, 2017.1.0b3, 2017.1.0b4, 2017.1.0b5
Cannot test for regression, Timeline was introduced in 2017.1