Pressing 1-9 hotkeys while hovering on an empty inventory or offhand slot does not swap the items

In Preview 1.21.120.23, the 1-9 hotkeys for swapping the items in the inventory has been added to the game. This works if you hover the inventory or offhand slot that has an item in it, but if you try to swap the items in the empty inventory or offhand slot, nothing will happen. This doesn’t match Java Edition.

Steps to reproduce:

1. Give yourself 2 items, and place them in any inventory or offhand slots (in this example, I use Shield and Totem of Undying)

2. While hovering over the items, press 1-9 key (in this example, I use 1)

3. The items swap to the hotbar

4. While hovering over the empty slot, press 1 again

5. Observe

Expected results:
The items swap to the hovered slot, regardless if there's already an item in it or not.

Observed results:
Nothing happens.