I was in a nephalem rift in torment X. I activated archon on the wizard and went through a checkpoint in the first rift map, cleared some of the second stage, when I revived at last checkpoint it was at the entrance of the first map.
Had this occur earlier today while playing a LoD-meteor wizard in a GR120.
Revive at last checkpoint on lvl 3 started me at the rifts entrance.
Certain maps do not have checkpoints. I would not expect them to add it.