Hi, I run across that discussion after I purchased a K-3III and noticed focus issues with 16-50PLM and non-center AF point... Basically I encounter the same weird behavior as several users in this discussion.
I didn't had time to do many tests at the moment but I am glad that I am not the only one to get issue...
As the others, the center AF point is working properly, but the others points are way off... for example, if I move 2 steps right with the joystick to align face/eye on the line of thirds, I cannot get sharp eyes... and it is far from being acceptably sharp... it is out of focus. I retried many times, and cannot get the eyes in focus.
So, after reading that thread, I tried other AF points, and some where BF, other FF...
However, focusing using the center point and recomposing work, but what is the point to have all that AF points and a joystick if I can't rely on them.. I'll have to do more tests but I am not sure that the issue is related to 16-50PLM... I quickly tried 70Ltd, and center was sharp, next point on right was BF, next one is FF
Also what is the point of focus tracking, if the AF points are all missaligned... very frustrating.
If only the body allowed to change AF offset for each focus points, and also for Wide and Long end of a lens... Do you think adjusting focus for all AF points is something that service repair can do with their own tools?