STEPS TO REPRODUCE
1. Launch iClone 6
2. Apply a project with Terrain Physics effect
3. Navigate to Scene Manager > Terrain > Canyon, then go to Modify, set the value of Smooth to 20
4. Click "Play"
5. Click "Undo" on Toolbar
6. Click "Redo" on Toolbar

ACTUAL RESULT
The Physics Collision can't update accordingly

EXPECTED RESULT
The Physics Collision can update immediately