I had a bunch of items in my van that were going to eventually become a new store (ovens and storage shelves, etc.), but I needed the space in the van, so I decided to move all my items onto an active/placed storage shelf inside another store.
Most of the boxes moved over to the active storage shelf just fine, but I had three boxed storage shelves on my handcart. When the 3 boxed shelves transferred to the active storage shelves in the store, it turned into only 1 boxed shelf. I pulled it off to confirm, and now I only had 1 boxed storage shelf instead of 3.