Memming rank 2 of a spell (or rank 3?) does not replace the existing rank in saved spell sets or spell slots.
That's not what the OP is talking about. In past expansions, if you have a spell memmed and get the higher rank version of that spell, the spell in your spellbar automatically refreshed to the new rank and you didn't have to redo the spell set. Now, it completely wipes that lesser spell rank out, forcing you to remem the new spell rank AND redo the spell sets.
It also leave the spell there when you click the rune to pick one. In the past it removed spells you already learned but now it just turns them red. I have not tried clicking a red spell to see if it tries to give you one you already know or not due to not wanting to waste a spell.
Previously it didn't offer spells you already had. It did offer combat abilities you already had, which was a bug.
Really? When the current behavior was added into the game, we were told that it was to help server load (or something like that). Has something changed?