Let's just go take a look at the related area of code. In this case, the story had to do with the way we were configuring samba, so I opened up smb.conf in a couple different scenarios (after upgrade, clean install, etc). And then I got confused about the story.
You see, when I actually looked at this, I saw some details that I had simply glossed over when reading the story. Nothing was too major, just questions about how it behaved across upgrades, and what types of changes would induce the desired behavior. And in the end there was a bug in there - we really did need to do some work and we hadn't thought of it.
The moral of the story is this:
Look at something, even if you already know what's going on. Some detail may surprise you.