First of all, Kasia Swiderska tested and confirmed this bug.
I created a post (http://cursocelulasmadre.com/jugadores-de-futbol-se-tratan-con-celulas-madre/) with PWL enabled.
Alt. URL to Like is: https://www.facebook.com/globalstemcells (my facebook page, so I get more Fans!)
The problem is when a person is already fan of my facebook page. The PWL blocks him from accessing full post.
In PWA settings there is some config to prevent this. But I cannot add the URL of the fanpage. Even after adding key and secret.
Access support is granted.