Installed two new 3 bulb post lights on concrete entry piers, one bulb pops and burns the base immediately upon installation... I have checked the wiring and everything is wired correctly, I assume ths is a bad bulb socket and the fixture is defective, has anyone had this problem before?

Possible the metal piece is touching the outer shell, a new socket should fix. You should be able to look in the socket and see the problem.