Issue with Dragging the middle element

Hi, in the below sandbox you can check, that after initial render. Any time you try to drag and put another element in the middle. It is not working, it always ends up a 2 item row, whereas in initial render it contained 3 items.

https://codesandbox.io/p/sandbox/q2cqr2

Start with the linked CodeSandbox reproduction and verify the initial three-item row, then drag another element into the middle. Trace the Packery drag-and-layout behavior responsible for the two-item result; done means the row retains three items after the drop.

Written by the indexing model from the issue text.