Difference between estimated nonground points and origin kitti point cloud

[kang-1-2-3]

I use offline_kitti.launch to generate classified point cloud, however, when I put the estimated point cloud and corresponding kitti odometry velodyne file in Cloudcompare, I found that there is a offset between them as following pic.

I only changed the pcd_savepath and save_flag in source code. Did I do something wrong? I tried patchwork++ and got same results.

[kang-1-2-3]

I did not sort file list.