Summary of the bug : Falling off the roof of the dome can sometimes cause you to either get stuck in the ground or fall through it entirely.
Which version of Grip were you using : 188.8.131.52
When does this happen : Racing in an arena.
On which track did it happen : Biodome.
On which speed did that happen (if related to physics) : Tested on Med and High.
How often does this happen : Reasonably common.
How to replicate the steps (if reproducible) : Drive up onto the roof of the dome and then brake so you fall off.
More details :
CPU: Intel(R) Core(TM) i7-4770K CPU @ 3.50GHz
Memory: 16 GB DDR3
Graphics card: Nvidia GTX 770
OS: Windows 10 Pro