Reproduction steps:
1. Create the new project;
2. Create Empty GameObject and add Cloth component;
3. Change Mesh to Plane and turn off Select Mesh window;
4. Change Mesh to Cube, turn off Select Mesh window and enter Play mode;

Actual result: Unity crashes in <physx::Sc::Scene::release> (actual_result.gif).
Expected result: Unity should not crash (expected_result.gif).

Note: if the scene is saved with the object which mesh is set to Plane and you open the project and change mesh to Cube, Unity not always crashes. However, Unity always crashes, if you repeat reproduction steps (when the project is new). The crash is caused because the bounds do not change after the Plane mesh.

Reproduced with: 5.5.0a1, 5.5.2p3, 5.6.0f1, 2017.1.a04
Not reproducible with: 5.3.7p4, 5.4.5f1
Regression introduced in 5.5.0a1