I think that the "problem" (or rather "effect") is caused by the basic physics of light and is inherent to all polarizers. Polarization will be at its maximum when facing 90 degrees to the light source (typically the sun), and at a minimum at 180 degrees (directly away from) or straight into the light source. Wide angle lenses though see a lot. The angle of view at 18mm in the horizontal (long) dimension is 90 degrees so no matter which way you point such a lens, one side of the frame will be much more polarized than the other.
Some polarisers pronounce this effect more than the others, but it's still visible.
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