I noticed this a few days ago, and was hoping it would fix itself, but I have doubles of items in my wishlists, and even if I remove it from my wishlist (which removes both) when I add it back in, there are two again.

This has been a bug for years now, unfortunately.

Edit: https://subeta.net/forums.php/read/867432

Thats the thread Bug sent to me to when they locked my other one talking about this.