The Yaw of base link does not stay relative to map.

[kay01-kwon]

Hi, I'm working with the mobile manipulator equipped with 2 velodyne, 4 encoder for wheels and t265 camera. However, when I configured the lua file by using ceres scan matching through tsdf grid map, the estimated yaw relative to map does not stay. I put more emphasis on occupied grid weight than translation and rotation weights to get more accurate pose data. Are there any reason why the yaw does vary even though the robot is stationary? The yaw relative to odom is stationary.