Unexpected elastic foundation interaction with varying stiffness

[Brandon Fugger]

Hi everyone, I currently have a model which includes a polygonal mesh and a sphere (for now) interacting with said mesh. These are both set to elastic foundation forces with default parameters. The mesh body is
40kg and the sphere is set to 1kg. With the default EF force parameters, I get expected interactions; the sphere interacts with the mesh. When I adjust the stiffness parameter to be 8000 N they will no longer interact and the sphere passes straight through the mesh. With some playing around, if I maintain default EF parameters and jack the sphere mass to 40kg, it also will not interact. Drop the weight to 1kg and stiffness to 8000N and they interact again.

Soooo. What am i missing here? Why do some of these parameters act unexpectedly. I am thinking some hysteresis issues but im not sure how to fix this. Thanks for the input