CEL code P0430
 

Went for a drive today & the check light came on, so I stopped by Autozone & have it checked out. The code comes up P0430 (catalyst system efficiency below threshold bank 2). I'm like WTF ?? I'd just replace bank 2 catalyst converter 2 months ago & the previous owner replaced it 4 months ago. Two cats gone bad less than 6 months? The cat is under warranty so I'm not worry about that. What concerns me is what would cause it to go bad that fast. It's a 2006 TT 3.2L w/89+K miles.

TIA for any inputs before I take it to the stealers.