Is it possible that Leras is not the original vessel for preservation? In Mistborn: Secret History the last thing that Ruin(or Ati) says is "Vax(?)". This is indubitably the name of another Vessel, the question being who. I believe that it is possible that when Preservation locked Ruin up, the power was not being held by Leras. I believe that Vax bore it, and when he attempted to imprison Ruin, Ati relinquished control to the Shard itself, going dormant. then, when Ruin wounded Preservation, Vax gave the power to Leras, in an attempt to vgive the power more time to lock away Ruin. Then, when Ruin was defeated, Ati awoke, and was confused when he saw that it was not Vax that wielded Preservation, but Leras.