Kangaroo getting repeated result

Hello people,
I was trying to achieve a form-finding using kangaroo2 to get a result like a figure below.


However, the result can only be reasonable when I slightly move the boundaries to a specific location. When I press the reset button again, with the same boundary location, I cannot get a repeated result. It will always give me a different deformation under equilibrium.
Sketch1
Can anyone help me with that? Thanks!
Here are the documents I have got now:
different results.3dm (52.7 KB) different results.gh (26.1 KB)