My character usually uses two one-hand weapons. They are favourited and assigned to the keys "1" and "2", one in each hand. I also use a spell, which is favourited and bound to the "3" key. When my character holds both weapons and I press "3", the spell appears in the left hand, which is fine. However, if I then press "1" to put the weapon back into the left hand, it will replace the second weapon in the right hand. The spell remains in the left hand. If I press "3" a second time, the spell doesn't go away, but it appears now in both hands.

Is there a way to go back to weapon+weapon by using the hotkeys? That is, without manually going into the favourites menu and left clicking the weapon that I want in the left hand. It's really cumbersome and breaks the flow of the game.
(Switching between 2H and 1H+1H/spell+1H/shield+1H all works fine for me, but I can't figure it out with the setup above.)