Unfortunately, the issue is still present.
Nevertheless, could you check if the following explanation about Windows Phone tiles will help:
"When you pass an iconic tile to Windows Phone, it converts all colored pixels to white pixels and then displays the converted tile. So if you have a square tile without transparent pixels, the result will be a white square. What you need to do is to have a transparent background and color only these pixels that you want to be displayed from Windows Phone. That being said, the default tiles of AppBuilder have the same issue you described. We are already working on new tiles, that will resolve this behavior.
Please, let me know if the above helps.
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