On the 2nd image going from the top-left corner, the tile has pixels using the same color as the background color.
Sorry, this is not intended to sound rude, but I can't make anything of it. I can't even figure what image in the sources you are referring too - "mall" is little scarce on the information part, at least for me, as I don't intend to check all translator entries for all buildings in the whole pak. So could you please give us a file name or a screenshot of the building along with the information wether it is a city house, an industry or an attraction, please? I'm more than willing to fix the problem, but only if I dont have to spend (much) more time locating the file than it will take to fix it. ;)
Also "2nd image going from the top-left corner" ... going right or down? ;)
Sure, no problem --
factories/shopping_mall.png
There's a line from (215, 77) to (215, 96) that is almost entirely (231, 255, 255).
PS -- after a bit of shading here and a bit of shading there...:
Ah ok... found it and corrected it. Thanks for spotting! :)