I wonder why? I remember the old VW 1.9 ALH TDi motors use to have issues with cyl #3 due to the fact the way the intake manifold flowed. No. 3 cylinder would always get a rape train of boost shot at it, and sometimes that #3 rod would bend. Not bend bad, but bad enough to cause a drop in compression in that hole, and sometimes hard starting and poor running.
Curious if that's the case on the 6.7?