Lab Won't Potty Outside

I have a 2 year old lab that was housebroken. During the past few
months he has become stubborn about going potty outside. When I take
him out he'll pee but refuses to poop unless I send him back.
Sometimes he'll still refuse. We bring him back in and within 10
minutes he'll poop in the house. We've corrected him and cleaned the
area and he still does it. We've left him outside for a few hours and
when we bring him back inside he'll still do it. We've been working
with him on this since it started and are quite fed up with it. Does
anyone have any suggestions?

--
Jerry