Oh, I don’t think Aurora’s returned heart was really Cora’s or anyone else’s.
When you mentioned it in your previous post, I actually wondered if you might be onto something. What reason would Cora have for taking Aurora’s heart with her to SB? Unless she could still use it to spy on them across realms, I suppose. I could see Cora wanting to take her own heart with her to SB though. Not knowing if she’d ever be back in FTL again, why would she leave her heart there completely unguarded?