Welcome to the world of NetApp
When you have Snapdrive, you just need the volume (and qtree) to be created, the rest does SnapDrive. For me it sounds like the LUN was created on the Storage and then you connected to the disk (instead of create Disk), thats where this behavior comes from.
If you use SnapDrive as it is ment to be, it will create the disk (LUN) partition it and format it.
Peter