Just a quick question but should the Kryptonite lock fall apart like this when it's open without they key in? To me it feels too loose but I'm not sure. Guess it locks anyways?
Yes and no.
Yes, that’s how they’re constructed - as two concentric pipes for strength.
No, as in they shouldn’t come apart that easily. You may have lost a retaining screw that keeps them together. You could also just glue the two shells back together with some metal epoxy, taking care not to foul the locking mechanism. Just a little epoxy is all you need as the strength of the lock is in how the lock shackle passes through the external cylinder. You could even flex- or duct-tape them together, again the lock strength is in the shackle passing through the two shells.
If you’re under warranty, you should get it replaced though. That’s what a warranty is for.