AssertionError in discrete action space when grasping

[meier-johannes94]

Hi, today I had the following error message, when I tried to grasp something in the discrete action space:

Traceback (most recent call last):
  File "stable_baselines3_behavior_example.py", line 242, in <module>
    main()
  File "stable_baselines3_behavior_example.py", line 199, in main
    observations, rewards, dones, infos = env.step(action_id)
  File "/is/sg2/jmeier/behaviorchallenge/iGibson/igibson/envs/behavior_mp_env.py", line 172, in step
    self.grasp_obj(obj, hand)
  File "/is/sg2/jmeier/behaviorchallenge/iGibson/igibson/envs/behavior_mp_env.py", line 351, in grasp_obj
    override_ag_data=(obj.get_body_id(), -1),
  File "/is/sg2/jmeier/behaviorchallenge/iGibson/igibson/robots/behavior_robot.py", line 1060, in handle_assisted_grasping
    assert contact_pos is not None
AssertionError 

[meier-johannes94]

It seems as if this error occurs quite often. This is really an urgent problem. At least for me. I am getting this error so often now. I think waiting for the new year / end of year for the next update would be a bit long ;-).

How can we fix this?