I hauled my Pacsafe backpack around Europe for a month with 45 pounds in and on the bag when traveling between my major stops. I took a tumble on the escalator in the Nice train station and fell on the pack, which not only protected all my gear but kept most of me from being chewed by the teeth on the steps as they ground past. My wife and a kindly helper hauled me off the steps by the backpack straps. No apparent damage to the bag or its contents, but my right leg was chewed up.
I also use the companies' camera strap when I'm in Europe--5 months in two trips so far and no problems. These all have similar swiveling links, so they can hold up.
Defective part, obviously. They should replace it.
If you are in a hurry, you can make do with a couple of small aluminum or steel D-rings in place of the swivel or key-rings in a pinch.