I have a Katadyn Hiker Pro and don't think any of my replacement filters have looked like that. I would send back or buy another just to be on the safe side.
Just an update, the replacement filter showed up looking the same way and I dug the old one out of my trash and it was similar. All I can reason is that is where the filter element is glued together?
I ended up using it this weekend so I guess we'll find out pretty soon if it worked or not....