Can you make sure you're still seeing this issue with new Like's on that page? I just Like'd it, and what shows up in my wall is below. You can see where the URL will take you in the address bar at the bottom, and it does indeed go to that page when clicked:
If you're still seeing that with the same account, try a different Facebook account. Facebook doesn't like it when a site changes the URL on a user as that can seem fishy, so it's possible they're using the original URL you shared instead of the properly updated one. Can't guarantee that, but just a thought. Still not sure why the apps URL
was being used, but again, I'm not seeing that now.
Thanks,
Alex