PZ 16-50 decentered?

I just got a NEX 6 with the PZ 16-50 kit zoom and started testing the lens to check its performance. I noticed that at 16 mm f 3.5 (wide open) the right side of the pictures are significantly softer as compared to the left side. Here are 2 crops, the second one taken with the camera flipped 180 deg (and image rotated accordingly).

PZ 16-50, 16mm, f3.5, crop of the right of the picture

PZ 16-50, 16mm, f3.5, crop of the right of the picture (taken with camera rotated 180 degrees) 

This is the full photo

PZ 16-50, 16mm, f3.5, full picture

This softness affects about 15% of the right side of the image, and it sharpens gradually when reducing aperture, being fine after f6.3. It is also less noticeable at longer focal lengths.

Is this "normal" for this type of kit zooms, or should I try to get it replaced? I am still within the return period.

Also, I'd appreciate other people posting their own images at 16mm f3.5 to compare and know what to expect.

Thanks!