After loading the Creative mode world, if my Item shortcut bar slots are empty, grabbing a block and placing it in the currently selected slot, then destroying the item, and then right-clicking will still place the previously selected block (without any placement sound). Upon re-entering the world, the previously selected block will reappear in the currently selected item shortcut bar slot.
This bug has existed since version 1.21.9, and subsequent versions 1.21.10, 1.21.11, and the current 26.1 have not fixed it.