Pluginlib ClassLoader giving severe warning when shutting down the move_base_flex node

[Kshitij1K]

System: Ubuntu 20.04
ROS Version: Noetic

Issue Description:
I ran the turtlebot3_mbf package with move_base_flex. Sometimes, when I shut down the node by pressing Ctrl C I get this severe warning:

Warning: class_loader.ClassLoader: SEVERE WARNING!!!
Attempting to unload /home/kshitij/ghar_ws/devel/lib//libnavfn.so
while objects created by this library still exist in the heap!
You should delete your objects before destroying the ClassLoader. The library will NOT be unloaded.
at line 119 in /tmp/binarydeb/ros-noetic-class-loader-0.5.0/src/class_loader.cpp

Should I be concerned about this?

I also wrote a dummy planner, controller, recovery behavior plugins and a navigation server class, based on the mbf_simple_nav. Running that also gives me the same severe warning when exiting, even though I have explicitly cleared all plugins and reset all action servers in the navigation server destructor, as shown in the code below:

  planner_plugin_manager_.clearPlugins();
  controller_plugin_manager_.clearPlugins();
  recovery_plugin_manager_.clearPlugins();
  
  action_server_recovery_ptr_.reset();
  action_server_exe_path_ptr_.reset();
  action_server_get_path_ptr_.reset();
  action_server_move_base_ptr_.reset();

Note that this warning only comes if I Ctrl-C shutdown the node AFTER I have given it some goal via the action server. If I shutdown the node without giving it any nodes, then the warning does not show up.