Ah! It's a P-lip, that's how they are. I would wipe out the bowl with alcohol real well, Peterson has a bad habit of staining the inside of the bowl and if it's not maybe the bowl coating is not to your liking. You can sand that out if you prefer. No sense in trying to send it back because you've already smoked it but, you may want to contact the seller and explain your problem.
If you do wipe out the bowl be very careful NOT to get any alcohol on the exterior of the pipe, it will ruin the finish quickly.