How do i reset my world without objects getting moved around?

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Hi guys,

im currently trying to implement a DRL agent as a robot in an environment.

after each episode im want to reset my world with these commands:

rospy.wait_for_service('/gazebo/reset_world')
reset_world = rospy.ServiceProxy('/gazebo/reset_world',Empty)

reset_world()

It works quite good but some of my obstacles get moved around to places where they werent meant to be.

Is there something that causes this and how can i get rid of it ?