Agent state memory keeps removed objects in memory

[thaije]

Describe the bug
In the BW4T task, picking up an object with the human agent does not visually indicate this: the object stays visible.
In the image below, the green square object has actually been picked up by the green triangle human agent, but it is still visible.

If you then drop it at some other location, the object is removed from its old visualized location and shown in the new location.

To Reproduce
See above.

Expected behavior
If an object is removed within sensor range of an agent, it should also be removed from the agent's memory so it is not shown anymore.