Theory:
In the alternative version of Mean 6 for G5, it was a surprise how the ponies inside the lighthouse are manipulated by Opaline Arcana's necklace, with the exception of Misty Brightdawn.

Which never had an evil version until Episode 6 "Swirlpool Starlight" of Season 2, where Mean Misty appears on the screen in less than 1 second and then returns to Misty's normal scene about the desire, despite not wearing the necklace, this Mean Misty didn't show any action, just looked.

Until this episode, she appears as a shadow or even subconscious, in any case, the color of her eyes maintains the same essence as in Episode 6 (Season 2), there is no denying that, it is in fact the same unicorn.