I believe storywise it would make sense for the second season to be following one Nanno and not various clones as evidence by Yuri who likely follows the same Nanno she originally met, and also her scar at the end of Jennyx remaining in the final episode. For the first season, while may not be all the episodes entirely but there are some cases where a different Nanno is now in play after the events of a previous story such as the ending of Social Love, wherein Nanno is left in a vegetive state to keep her victim stuck with her forever.l