An uneven map appears when creating a map on a flat surface

[nanbwrn]

When I used it to build an elevation map for the quadruped robot, I found that even when the robot is on a flat surface, the created map is uneven. This causes the robot to move very unstably. Could you please suggest which parameters should be modified to improve this? Below are my settings for go1_core_param.yaml, go1_example_setup.yaml, and convex_plane_decomposition.yaml. Thank you all for your responses.

convex_plane_decomposition.txt go1_core_param.txt go1_example_setup.txt plugin_config.txt