This happened both times on Livonia.

Seems to happen whenever you drive over an item or crash.

First time driving an ADA car, reversed the car and crashed into a post from a watchtower and the car flew into the air and travelled some distance.

Video: https://youtu.be/IEcQJL_fnHk

The second time we got back to base and our blue truck was sitting on a hill side (was impossible for someone to drive this out) so got in the truck to try and move it and drove over a tree stump and same thing happened again, the truck went flying into the air and the player is dead.

Video: https://youtu.be/z6EX7W_E7fk