I had some repairs done under warranty this year. My D600 stopped metering and they spent five to six weeks to "RPL image ctl pcb, rpl connector fpc, rpl aperture coupling ring". The AF on my 24-70 stopped working, and I was shocked by this one, as the lens very likely had impact damage from having it in the back of my boat while whitewater kayaking. They fixed it under warranty in a week and a half, including shipping. "rpl cam ring, rpl roller guide ring, rpl focusing ring".
Sounds like they may be responding to all the negative criticism, or I just got lucky. (dm)