Steps to reproduce:
1. Open the user's attached project
2. Open scene "Demo 3" under Assets\LowPoly Environment Pack\Demo
3. Select "Grass" gameobject and uncheck Static box in the Inspector

Expected result: No errors are thrown when un-checking Static box
Actual result: When un-checking Static box, exception is thrown: "InvalidOperationException: Operation is not valid due to the current state of the object
System.Collections.Generic.Stack`1[UnityEditor.PropertyGUIData].Pop ()"

Reproduced with: 2017.3.0b1, 2017.3.0b6
Not reproduced with: 2017.1.2p2, 2017.2.0f3
Regression introduced in 2017.3.0b1