It seems that if, in rapid succession, if one creates a
file, then deletes it, then creates a directory, the
directory receives the same inode as the deleted file. The
file information is still cached, and nfs does not see it as
a directory. ls does, list it as a dir most of the time.

This happens on RedHat Linux 5.1 and 5.2, and 5.2 with
kernel nfs. The clients are Solaris and Digital UNIX.