I have noticed the error message: kernel: NFS: Buggy server - nlink == 0! ...both on our demo system and on UERJs cluster. I've not managed to repeat this problem, though. UERJ is running 1.5.0 clients. I'm not sure if this happens with recent versions of unfs3, though, but we should watch out for this.
See also thread at http://marc.info/?l=linux-nfs&m=118111763020734&w=2.
We've not seen this in a very long time, so let's assume the issue got resolved.