This is meant to be a square with slightly rounded corners and a pointed bit at the bottom. However, due to the poor downscaling the top and bottom edges of the square have become blurred and the background is bleeding through.
This is a remarkably simple thing to fix if one has high-resolution versions of the icons. As it is I don't, so I'm just going to briefly recreate them for my community (I might as well post them here when I do just in case anyone wants them). Ideally though I'd prefer this be rolled into the official skin so it's not necessary.
I've not noticed this affecting any other icons, but those two in particular stand out like a sore thumb on a high-quality screen.










