I am facing issue adding product in wishlist (magento version 2.2.3).
Here is scenario,
Step 1 :- Make sure customer not logged in.
Step 2 :- Go to product list page and click "Add to wishlist"
Step 3 :- it will redirected to login page.
Step 4 :- Now after social login it may be facebook,google you can check product not added in wishlist.