Comment 27 for bug 65003

This isn't a coreutils bug; it genuinely can't remove all the files (counting the NFS dotfile) and therefore can't do the rmdir(). If anywhere, the bug is that the NFS server is implementing access to still-open unlink()ed files by means of a dotfile in the same directory as the link, which means you can't do unlink() and then rmdir() without closing any fds you have open on the file as well.

This suggests a different workaround in debootstrap; I'll post a suggested patch shortly.