YITH WooCommerce Product Add-Ons: cannot remove add-on

Hi
I created some fields (2 extra input fields) for several products with the YITH WooCommerce Product Add-On, and chose to show the extra fields for 3 products. I later decided to show the extra fields for only 2 products, so I removed on of the product fro mthe list “Show in products:”.
Unfortunately, the extra fields still show up in the product I removed.

The page I need help with: [log in to see the link]