Hello,
Click on the wishlist icon if the product was already added to the wishlist means “browse wishlist” it does not remove from the wishlist and never did that. This is how YITH Wishlist plugin works and we can’t change this.
Don’t see problem with the heart icon https://gyazo.com/fea078f52c310d6455f844a09d8054af It’s read if the product is added to wishlist.
To remove double icons on the single product page follow the docs https://www.8theme.com/documentation/xstore/plugins/wishlist/
Regards