wierdness with NFS in -current or RELENG_6 (?)

server: FBSD RELENG_6 (within the last couple weeks), i386

client: FBSD -current (yesterday) i386 [1] or either i386/amd64[2], or linux[3]

1. Mounted a directory from the server, not reserved port, otherwise
default. A normal file on the server appeared, briefly, as an empty
directory (!!!!).

2. The 'ro' qualifier in fstab seems to be being ignored.

3. Linux RHES4 cannot reliably mount NFS from the above server- one
out of 3 times it hangs. It's usually convenient to blame Linux, but
the problem goes away with combinations of restarting mountd or nfsd
on the server.

Anyone else with the same experiences?