Why is the simulation result based on reduced order flexible solid wrong?

I established the dynamic model based on Reduecd order flexible solid and flexible cylinder beam respectively. Fix them with the ground one the one end, and exert pulse on the other end in X direction. But obviously, the simulation result with reduced order flexible solid is wrong, there is deformation in Y-direction. I have checked the model several times, but didn't find what's wrong with it. Could you help me with that?

The simulink file and other related files are attached. When you run the simulation, run tets.m first, input [3,2] when asked to select faces. Then open simulink file and run it.