Has anyone ever seen this?

I just finished a brake job, Hawk DTC 30 pads, Brembo rotors and complete flush with Motul 600 fluid on a 1990 Honda Civic Si with integra rear disks. After I finished i took the car out to bed in the new pads. Leaving my neighborhood everything sounded and felt fine. So I started the bed in. 4-5 moderate braking from 35 down to 10 then another 3 hard braking from 50-55 down to 10.

After this I turn around to head back to my neighborhood. That's when I start to hear scraping. I pull in to my garage to find my rear passenger brakes like the pics below. Both the inside and outside of the rotor are scraped up and both inside and outside pads look similar. All the other wheels are just fine.

What could cause this? Faulty pads? Rotor?

When I first saw the rotors with the wheel still on I thought the hardware was digging into the rotor, but that's not the case, it is no where close to touching.

 

We're they super hot when you removed them? Looks like the pads got twisted in the slides. Sometimes if pads go in "hard" Into the slides I'll grind a bit if the finish / paint off of the tabs of the pads. I don't see any lubricant in the ends of the pads ( may just be the picture). That may have been why they couldn't move properly.

Id machine the rotor. The pads are probably usable, just need to be cleaned up a bit. Unless they are super worn out on that outside edge

 

Now that it's not 2am I see what happened after looking at them more it looks like the notches in the caliper piston got twisted on the dimple in the rear inside pad and caused it to start dragging and heating up.

I never had this happen before in 30+ brake jobs, but I'll be sure it doesn't again.

 

That is a classic install error, and is often overlooked even by professionals. I've done one too many brake jobs where the upper half of the pad is completely gone and the bottom is practically new.