Stupid parts question, but...

Went through the same thing a couple of weeks ago when replacing the calipers on the '06 2500.
The caliper pistons were getting hung up on the rivets that hold a thin piece of steel on the back of the pads. Found that out when the ceramic caliper piston broke from pressing on the rivet head. It was obvious when looking at the rings that make contact with the pad...there were indentations on the rings caused by pressing on the rivets.
A temporary fix is to grind down only the rivet heads that will interfere with the pistons.
Although they refunded everything, Autozone/chink parts are no more for me.