Android: Error in destory

[dddj698]

Hi，
I'm development an Android app with filament to render 3d objects, however when I call engine.destory(), I receive an error message:
in destroy:1070 reason: destroying material "base_lit_opaque" but 26 instances still alive.

Do I miss any steps in clean up? currently code I have:

              MaterialBuilder.shutdown()
              uiHelper.detach()
              engine.destroyEntity(light)
              engine.destroyRenderer(renderer)
              engine.destroyView(view)
              engine.destroyScene(scene)
              engine.destroyCameraComponent(camera.entity)
              EntityManager.get().destroy(camera.entity)
              EntityManager.get().destroy(light)
              engine.destroy()

Thanks for your help in advance.