We have seen that in Game of Thrones Season 4, Melisandre did not wear the necklace while in a bathtub, and she is looking normal. But in GoT S06E01 she takes off the necklace to reveal her true identity
as a very old woman. Is it that she aged that much between these 2 seasons?
Is it a mistake in the show runners' part or is there any other reason why she didn't appear like that without the necklace earlier?