Rubber compression Simulation

I am simulating a rubber component where rubber has a self - contact as it compresses, but i can see through animations that elements are intersecting and penetrating.

I have defined type 19 self -contact (with Istf=4 and inacti 6 and igap =1) by using surf cards via components.

and used mat 42 as material card and Isolid 24 as formulation. with material property.

The model is in volume cavity and can only displaces in gap  between it and load is applied horizontally by displacing a rigid shell along outerbody in horizontal direction and rigid element with internal nodes of rubber is fixed in space.

 

Cut -section displacement <2mm (gap is 2mm) and element start to deform at before gap reduction

 

 

element distortion and time step is reducing .there is penetrations and intersection between elements despite self-contact

 

what should be contact parameters or any other input to avoid such behaviour?