How to reproduce:

1. Open any (new) project
2. In the Physics Settings, set the Broadphase Type to Multibox Pruning
3. Import attached script
4. Attach script to any GameObject
5. Set the World Extents value to a legitimate one (like 10,10,10)
6. Play the scene, then stop playing the scene
7. Set the Subdivisions value to some value less than the largest value used before
- Note there are errors in the console
- The errors stop appearing if the value is reset or increased

- The same behaviour is not reproducible when using the Physics Manager window