Addon don’t close errorfree (xbmcgui XML error)

Hello

By disabling my addon from addon information dialog, i get this error on kodi.log:

Code:
the python script "/home/osmc/.kodi/addons/plugin.script.ibuscommunicator/service.py" has left several classes in memory that we couldn't clean up. The classes include: N14PythonBindings36XBMCAddon_xbmcgui_WindowXML_DirectorE

after enabling the addon again and opening the same window, it gets a new ID.
on leaving the window closes normally with close()

in addon shutdown i added an extra close() event. so kodi.log tells me, the window -10000 could not be located.
doModal() or show(), close() has no difference for result.

System: Rasp with OSMC

Is there a way to solve the problem?
How to find out what process let hold the window?