I thought he crowded the middle too much on defense, worried about penetration obviously, which left the wing wide open and hard for the forward to get there. I believe they screened the forward on his side twice while he was on and got wide open 3's.
That being said I've been high on his D all season and was as others very impressed with his calm and ability to put the ball on the floor, split the press, draw the D and get it to a big by the rim. He made that short jumper look like he could make it everytime, he should do that a lot more.
It seems to me he will be a solid contributor down the road in his career and probably have a few games each season were he goes off from 3 and kills teams.