If you hover over an item inside your inventory using “Full Keyboard Gameplay” and close it, it will shift click any item you last touched into ur inventory/hotbar.
It continues to happen even if all the keybinds are customized in a way that does not select and item associated with the inventory key.
This does not happen with “Full Keyboard Gameplay” disabled and works as intended.
Please edit your report to change the Affected Version to the version shown on the Minecraft title screen