Playing with Mouse/Keyboard.
I was playing as a Client. I was driving a tractor with 2 trailers attached, a worklight and a small generator attached to the front of the tractor, and a medium storage on the 1st trailer.
When I got in and drove off, a my 2nd trailer detached automatically (a well known and common bug when playing as a Client).
I turned around to go back to get it. I drove near it, and hopped out of the vehicle. The vehicle had not come to a complete stop. It looked like the nose and/or the front wheel or two of the tractor dipped below the ground plane slightly. As it was partially going through the ground plane, it began jerking around. The wheels begin shooting around in various directions. After a few seconds, it suddenly jerked into the air about 30 or 40 feet, and seemed to be stuck in the air (with the physics forces stuck in a feedback loop or going beyond normal limits). The host commented that he could tell something was happening that was slowing his PC down a little bit.
Maybe within 5 or 10 more seconds, the vehicle was gone. I assume it was launched into space or some other inaccessible place...
This kind of bug doesn't happen as often as it used to, but it's a very old bug... Similar feedback loops would happen at the very start of early access. Is it not possible to put constraints on the physics, or detect when it's in such a state in order to reset it or something?