There is no pattern in your sample. So please create a new thread and describe step by step what exactly you are doing and when exactly the issue appears.
What is the size of your icons in Illustrator measured in pixels?
What are the top left XY coordinates in pixels in the Transform panel?
It is important to have the artwork and also the Artboard placed fully within integer/whole pixel X and Y values in the Workspace, which means that the X and Y values at the corners must be integer; this can be ensured by using one of the corner Reference Points in the Transform palette, and then checking that all the values X, Y, W, and H, are integer (the centre Reference Point can only be used if both W and H are even numbers). Otherwise the resulting image will become a bit wider/taller and the extension(s) will be empty and therefore be (partially) transparent/white or otherwise ugly.
Maybe irrelevant here, but to retain the clean and crisp artwork, a PNG must be created at exactly the pixel x pixel size that it is to be used for, or at sizes that are powers of 2 times as large (2, 4, 8, and so on).
And for clean and crisp artwork avoid JPEG.
That makes sense, Jacob. And I doubt that I can locate the corners of the images as integer pixels because the image source is likely not the best one. It might have been jpeg images. I'll go back to the source of the images.
All raster images have sizes in whole pixels, so they can easily be moved to whole pixel positions; you can just use one of the corner Reference points in the Transform palette and set the X and Y values to whole numbers.