[dnanian]

Oh dear, no, not at all. /Volumes is where drives are mounted by OS X. A mounted drive looks like a folder in there. But if the drive "Vanishes", and the folder is left by orphaned, we can't always tell it's gone. If we keep copying, rather than going to the volume represented by the mount point, it goes into a folder.

It's rare, but I think it's happened in your situation.