It seems that, while setting new center coordinates, the "square" thumbnails creation process does not take in account this.
Providence correctly save the position of the new centerpoint, but widepreview, widethumbnail, iconlarge and icon representations are still generated around the true image center and not the new centerpoint.
Media plugins info:
GD Didn't load because GraphicsMagick is available and preferred
Gmagick Didn't load because Gmagick is not available
ImageMagick Didn't load because ImageMagick executables cannot be found AND Didn't load because GraphicsMagick is available and preferred
Imagick Didn't load because Imagick is not available Not available