Bingo. So it is corrupted alpha channels. I've experienced them before. Repair them. I don't know what image editing program your using at the moment so I can't help you yet but heres a quick way on how to do it (will erase team colour though)
Convert the .tga to 24bits and use WC3 Viewer to convert it to a .blp, adding a opaque alpha channel.
That will work, but there are other ways too to repair them.