Possible BIG problem 16-50 with Nex 6!

Here's the rub: the lens will focus.  You have demonstrated it can when you adjust the focus to what you want it to focus on.  So it is the implementation of the choice of focus point that is either not working, or not working the way you expect it to -- but the lens is focusing, just not where you want it to.
Can this be a function of the lens design?  Personally, I don't see how.  Whether PDAF or CDAF the system is looking at something that is sees as in focus ... A lens flaw would be never sharp.  Or sharp in the middle but not the edges, or on one side but not the other -- but choosing to focus on the wrong thing?  Still having a hard time seeing that as a flaw ...
Cheers,
GB

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http://www.flickr.com/photos/geoffbaker/sets/72157632181672263/detail/