The issue #390 is still an issue in ROS melodic. This means that if you use the pose_based_cartesian_traj_controller or joint_based_cartesian_traj_controller with ROS melodic, the robot will move slightly over time when no commands are sent to the robot exactly as stated in issue #390.
I think the issue is that the cartesian controller has only been released for noetic and not for melodic, after the issue has been fixed. This can also be verified in PR #474 which includes tests to test above issue. It fails on melodic, but not on noetic.