Compared to 1.12 inventory actions are less responsive. What I actually mean is that in 1.12 if I placed something in my off-hand and closed the inventory right after it would stay there. In newest versions of the game it is not the case anymore. Instead, when I do the same, the item often just drops from my inventory as if I had it under my mouse cursor (even though I placed it in the slot). In fact that happens for all inventory slots as long as I place/switch items and close the inventory too fast for the game to register the action which I think is the case.