Had the same issue just yesterday, pretty game breaking... kills the immersion for players...

Another examples:

Can be applied in engine as workaround?
Dead bodies in ragdoll (incl. when unloading bodies from vehicles) will turn off it's collisions with ground vehicles (may be CarX, TankX etc.) until isAwake is equal to false?

upd: when dead unit moves from vehicle its collision+ragdoll can hit vehicle to fly as like from videos above

^_^