Update: fixed. The store now shows 1.6.2 (released Oct 14). It switched within about an hour of removing all Creative Assets (header + search result asset, on the default and custom product pages). The header first went live Oct 7, the same time new versions stopped reaching the store. Apple support also escalated on Oct 13, so the cause isn't confirmed. If you're stuck on an old version with Creative Assets live, try removing them.