I am playing the most recent version of KSP. Since the update to 1.3.1, I find that my spacecraft bounce up off celestial body surfaces right after "physics easing in progress." This has happened on Dres, Ike, Pol and Gilly. In all instances, the craft were stable before a game save and/or navigating to them in the tracking station. It has happened both with and without drills deployed. Most recently, I landed on Gilly and saved my game with my craft stable and everything shut down. When I reload the game and go to this scenario, the “bounce” of the ship after physics easing launches my spacecraft back into orbit. Frustrating to say the least.
It also makes no difference whether landing gear is deployed or not.