still seems to need a kick
Well, the problem is that our servers tend to reboot at arbitrary times (essentially they crash). I suspect small power outages in the datacenter by now. Anyway, every once in a while the database is not repaired properly upon startup and what you have seen is the result. This is no drama - it just requires a manual repair run.
Actually I didn't notice the problem because the rest of the forum worked fine - just the New Content was affected and I simply don't use this function. The issue occurred during my vacation and the rest of the team didn't know what to do about it obviously.