The http://osdn.dl.sourceforge.net/sourceforge is sourceforge's primary mirror. All new releases are published here first. I am not aware of the update interval of the mirrors present in the current thirdpartymirrors-list, but with very recent packages, I cannot automate the download because the file is not on gentoo mirrors nor on any listed sourceforge mirror. Please add http://osdn.dl.sourceforge.net/sourceforge as the lowest priority mirror in your list.
Fixed in CVS though I have no clue why this stuff gets to QA... heh