While we've experimented with various solutions to the Release objects issues noted elsewhere, the release managers made various changes to the set of published releases (using the Downloads -> Releases interface). This has had the effect of changing the contents of the buttons on the Downloads pop-up. It seems that the values of the buttons do not change immediately when the releases are deleted or possible updated (possibly with a release that was not fully populated with release files for the operating system being viewed from). On several occasions, the Python 3 button has had no text or link associated with it; this is the case at the moment for me. It's not clear how to reproduce easily without negatively impacting the site.