Hello. I'm getting unstable contacts when using heightfields with small robots (30cm). The robot shivers when in contact with the height field. I reduced the margin to a very small number and this helps somewhat, but I'm still getting moments where the leg goes through the floor and the whole thing blows up and flings the robot up in the air, completely messing up the reinforcement learning procedure. Any advice on how to set the simulation parameters? I've attached an XML that I'm using. Thanks in advance, T.