Let me guess, you where on an object and then deleted it after some time?
If I'm right, it means that it's not really a bug but and optimization (or to be precise, a unhandled condition in an optimization).
LFS (or any physics engine), put a rigidbody into "sleep" when it is no longer moving (and after a while), to save performance. But when you remove a object, LFS doesn't "wake up" objects that are near it.
of course not, we did long time for qualifying that track ( layout ), then we did all go off, and so on, no one did remember anymore, I did not even remember either, but it was raw record straight to youtube. I did remember then when I logged in next time, and putted vid on public...
...HOWEVER, I think I can reproduce it, this is possible by the way to do on Blackwood, before Turn 1 on GP layout, but that was like 4-5 years ago... But that looks more like it's car's skirt gets on touch to ground, so, it was not miracle thing then.