How do I remove listings from the ‘product sync needed’ filter on the active listings page?

The “product sync needed” filter on the active listings page indicates any item whose quantity has changed since the last listing download.  This does not indicate that the qty is incorrect on your storefront.  To remove products from this filter, you may perform a listing download from the storefront.  

You may download listings by hovering over Quick Actions (lightning bolt icon) > Download Listings, select your storefront > Click Go.