Rear brake blocks replaced

Hello together, on Friday I saw something that I haven’t seen in 32 years car making yet. My brake back right made metallic noises, so I got new blocks at the FOH for € 70.70 (which didn’t even cost DM 50,-?). Friday afternoon I changed the right side, the outer surface had still a good 6mm and the inside was no longer available. On the left side then the shock, the outside again 6mm and the inside (approx. 4mm) lies loosely between stop He and Scheibe. I’ve never seen the coverings replace each other. Since I have been driving the car since KM-Stand 65,000 (now 145,000), it must be the first and no cheap goods. Has anyone ever had this before??? If something like this happens when I drive with my boat back through the Alps, coastal road etc. ohwehohwehohweh! Greeting Werner