I'm not surprised, I'd imagine the conversation at MS went something like this:
Engineer: There is one notable bug, network drives don't work properly.
Manager: Well, this update is only going out to home users initially and this issues won't affect home users right? I mean, which home users use mapped drives?
Engineer: Some users may have NASs, or may map a drive for sharing files between two home computers?
Manager: Yeah, but they'll be in a minority, and besides we don't really care about home users anyway.
Engineer: I dunno, it's quite a noticeable bug that will affect some people.
Manager: I don't really care. So long as it won't affect business users, we're OK. The update is overdue and our marketing people really want to get it released ASAP.
Engineer: It might also hit some small busine...
Manager: I don't care! Just get it out there now. Meeting our twice-yearly releases on-time is far more important than a few bugs.