Comment 57 for bug 506798

This problem is really no different than how autofs works. When you run stat on an autofs mountpoint, you'll just get the directory until you walk into that directory.

That's actually correct behavior since you're adding a new mount when that occurs. This is almost completely the same thing, it's just that the kernel does a new mount w/o needing autofs.

I'm not sure this is actually bug, rather you're just seeing expected results when the kernel adds a new mount on the fly.