A bug that causes the game to skip inventory slots when picking up items.

Fill the players hot bar with various items.

When in the creative menu, throw a new item that won't stack with any hot bar items, onto the ground, keep the creative menu open on any page that is not the player's inventory during this.

The item will be picked up as usual, except the item will be deleted and not in the players inventory.

Repeat step two, but with the player's inventory open.

The item will be picked up and will show up in the inventory, except it will be 1 slot along from where it should actually be, essentially skipping a slot.

Whether or not the item deletion is a bug or not I'm not sure, But the game will no longer place items into this slot until an item has been moved in and out of the slot.

After doing some testing, repeating step 2 allows the player to block more slots. This can be done until the player has blocked their whole inventory, and any item picked up afterwards is deleted.