I'm still scratching my head on this one. Hopefully a HP-UX expert will chime in at some point.
Another thought is could the NFS versions on these systems be different???
Often you can specify the version (2, 3 or 4) on the 'mount' command line but I don't know whether that option (eg, '-o vers=3') is available in HP-UX. If the NFS versions are different then that will cause trouble.
Also, perhaps you should be putting '-F nfs' option on your mount command. Again, I'm not sure about HP-UX.
Also, I would think about setting the protection mask on the /public share to 777 until this issue is resolved to ensure security isn't getting in the way.
I'll continue to think about this one.
---------- Post updated at 12:55 PM ---------- Previous update was at 12:35 PM ----------
This page from the HP forum:
how to check NFS version - Hewlett Packard Enterprise Community
states that you can specify the NFS version to use on the mount command with '-o vers=<2, 3 or 4>'
Also it would be worth checking the supported NFS versions on all HP-UX boxes (in case they are different) and the Suse box.