The indoor shots look as if the camera is tilted every so slightly downward. I'm going by the perspective distortion by the window. The brick wall looks perfect. You might be a little bit thrown off by the ultra wide distortion that is stretching the bricks in the corners. This is a characteristic caused by optics when three dimensional scenes are projected onto a flat surface.
From those five images, your lens is working as well as any 12mm lens out there, much like mine. Now you need to stop worrying and just enjoy the lens. Too much pixel peeping ruins the fun, I find when I start doing it (and we all do, mostly).
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