When this happens and there are 3 profiles to be merged, they should each be done to the lowest profile ID. Since the Unknown has been merged to the Bailey-2418, there will now be another merge done into the Bailey-713, so that Unknown Record will have 2 merges, instead of one that should have been done. As Gaile said, we want to merge the least number of times, when possible. Changing Last Name at Birth is the same as a merge.