MoveIt! PlanningSceneMonitor fails to find 3D sensor plugin

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I've set up a custom node for motion-planning of a robot using MoveIt!. The robot has been set up using the MoveIt! Setup Assistant.

The robot has a 3D sensor mounted on it that is used for identifying obstacles to navigate around. To do this I have defined a 3D sensor plugin in the sensors_3d.yaml file.

sensors:
  - sensor_plugin: occupancy_map_monitor/PointCloudOctomapUpdater
    point_cloud_topic: /robot/robot_collision_pointcloud 
    max_range: 50.0
    point_subsample: 1
    padding_offset: 0.1 
    padding_scale: 1.0
    max_update_rate: 1.0
    filtered_cloud_topic: filtered_cloud

Later the obstacles should be removed again.

I am trying to clear a pointcloud / Octomap Occupancy Map from the environment using the built-in functionality clearOctomap() from the MoveIt! PlanningSceneMonitor.

However, upon starting the PlanningSceneMonitor interface the following error is thrown in the console output:

[ INFO] [1602157700.053733888] [ros.deicer_motion_planner]: Request planning scene succeeded.
[ INFO] [1602157700.053767604] [ros.moveit_ros_planning.planning_scene_monitor]: Starting planning scene monitor
[ INFO] [1602157700.055528926] [ros.moveit_ros_planning.planning_scene_monitor]: Listening to '/move_group/monitored_planning_scene'
[ INFO] [1602157700.058323281] [ros.moveit_ros_planning.planning_scene_monitor]: Listening to '/attached_collision_object' for attached collision objects
[ INFO] [1602157700.058352982] [ros.moveit_ros_planning.planning_scene_monitor]: Starting world geometry update monitor for collision objects, attached objects, octomap updates.
[ INFO] [1602157700.059608477] [ros.moveit_ros_planning.planning_scene_monitor]: Listening to '/collision_object'
[ INFO] [1602157700.061673432] [ros.moveit_ros_planning.planning_scene_monitor]: Listening to '/planning_scene_world' for planning scene world geometry
[ WARN] [1602157700.062136986] [ros.moveit_ros_occupancy_map_monitor]: Resolution not specified for Octomap. Assuming resolution = 0.1 instead
[ WARN] [1602157700.062168852] [ros.moveit_ros_occupancy_map_monitor]: Target frame specified but no TF instance specified. No transforms will be applied to received data.
[ERROR] [1602157700.062688762] [ros.moveit_ros_occupancy_map_monitor]: Failed to find 3D sensor plugin parameters for octomap generation

I am starting the PlanningSceneMonitor with these lines of code:

planning_scene_monitor_ptr_ = std::make_shared<planning_scene_monitor::PlanningSceneMonitor>("robot_description");
// planning_scene_monitor_ptr_ = new planning_scene_monitor::PlanningSceneMonitor("robot_description");

// update the planning scene monitor with the current state
bool success = planning_scene_monitor_ptr_->requestPlanningSceneState("/get_planning_scene");
ROS_INFO_STREAM("Request planning scene " << (success ? "succeeded." : "failed."));

// keep up to date with new changes
planning_scene_monitor_ptr_->startSceneMonitor("/move_group/monitored_planning_scene");
planning_scene_monitor_ptr_->startStateMonitor();
planning_scene_monitor_ptr_->startWorldGeometryMonitor();

These lines of code are used to clear the Octomap:

const planning_scene::PlanningScenePtr planning_scene_ptr = planning_scene_monitor_ptr->getPlanningScene();
// planning_scene_ptr->getWorldNonConst()->removeObject(planning_scene_ptr->OCTOMAP_NS);
// planning_scene_monitor_ptr->triggerSceneUpdateEvent(planning_scene_monitor_ptr->UPDATE_SCENE);
planning_scene_monitor_ptr->clearOctomap();

It seems that the sensor plugin and the associated parameters cannot be found by the PlanningSceneMonitor. Despite this, I can still send data on the sensor plugin topic, which shows up correctly and is correctly being avoided when motion-planning. Additionally, clearing the Octomap from the MoveIt! MotionPlanning panel in RViz succeeds.

I am running ROS Melodic 1.14.9 on Ubuntu 18.04 LTS.

MoveIt! version: 1.0.6-1bionic.20200828.224341

Minimal working example below:

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