Yeah he needs to hang the gloves up pronto given the way he's always been a magnet for punches. The guy is just putting his health in jeopardy at this point.
To be fair he'd only fought once in over 3 years going into this match up and that was against a 38 y/o who was 0-4 in his last 4 fights and has lost his last 6.
Punch resistance has gone due to age, wear & tear & inactivity.. it happens. He's been the distance with men like Salido, Beltran, Burns, Burgos etc & only been stopped 3 times in 37 fights.. one stoppage YEARS past his best. Gamboa was probably juiced anyway.