When a downloaded file fails to fit the digest file, gentoo tries alternate download locations. The problem is that with wget the new file get's .1 appended to the name, so even if the new file is ok, it will never be used. The best solution would also check first for filesize on ftp mirrors so downloads are not in vain. Next before downloading from an alternate location, the original file should be renamed to something else.
we're a bit limited by wget here, but portage 2.0.22 should show some improved behavior.
