Shouldn't retcon nannasprite have died, like how retcon Davesprite did?

She should! It’s yet another thing that makes me believe the post-Retcon Timeline is beyond the Alpha at that point. Either that or, Harlequins are just as incoherently hard to kill as Clowns are.

Or even more worryingly, that one of them may still be, indeed, doomed and marked for death soon after the events of the Credits.