Pretty much strange, isn't it?
Is the NFS (Linux) Client you're moving between rooms really unable to ping the NFS Server from the room served by JE006A? is the same NFS (Linux) Client capable of doing ping to NFS Server when it is connected via the JE009A?
Is the NFS Server connected to what (3rd Switch)? what is your network topology (doesn't matter if it looks simple, tell us about that).
If so, how clients rooms' switches are interconnected to the NFS Server? ...via this 3rd Switch that has two downlinks, respectively to Switch JE006A and Switch JE009A?