On the Special:Adoptions page, the Big Heart badge is shown, but not the details of the requirements to receive it. I suggest two possible fixes:
1) the page could also say that you only get the badge by adopting from that page, and that if you click on the profile to review it first, and adopt from the link there, no badge.
2) also award the badge to those adopting from the profile page. I prefer this option, but I don't know the technical aspects.