I don't know if it's a duplicate bug:
When you send a robot to recycle an item, the robot still think that it has that item in the inventory, although the visual effect and ability of the item disappeared, and the robot cannot pick up any other item - I tried to make an infinite loop of having a robot recycle a bucket whenever he milks a cow, and then make the robot make a new bucket from the resources received by the recycler, this loop would milk the cows without ever filling up the milk storage.
If you take the "non-existing" bucket from the robot you will get the bucket, and if you place it down anywhere you cannot pick it up anymore.
You cannot do anything with this non-existing bucket.