This wouldn't be exposed as a fault Lee if the cam signal is taken from the cam pulley. If the cam shaft has rotated independently then the cam/crank sync & plausibility will appear to be correct.

You have to consider where the signals are picked up from.

I am sure you have seen many times where cam/crank timing checks out correctly, only to find some deviation when a further strip down is performed.

Renault 1.5 Dci are a common one that immediately spring to mind.