The anvil is bugged in the last update. Under the right circumstances, you can get multiple versions of some legendaries. It'll be fixed for the next upload.
Do you have the newest game version? A previous version had a bug, in which you didn't get Tiena's orb when you had the orb of the ice queen. But that was fixed by now.
Otherwise, there is no easy way to get the memory orb. You can only get it from defeating her.