FreeBSD 15-20250822 NFSv4.1 server broken?

Good morning!

FreeBSD 15-2025082, NFSv4.1 server set up like this:
# sysrc nfs_server_enable=YES
# sysrc nfsv4_server_enable=YES
# sysrc nfsuserd_enable=YES
# sysrc nfscbd_enable=YES
# sysctl vfs.nfs.enable_uidtostring=1
# sysctl vfs.nfsd.enable_stringtouid=1
# sysctl vfs.nfsd.issue_delegations=1
# printf 'V4: / -sec=sys\n' >>'/etc/exports'
# service nfsd start
# cat /etc/exports
V4: / -sec=sys

Linux 6.16 kernel, attempting to mount and use:
# mount -o vers=4.1 10.49.202.66:/nfsdata /mnt_freebsdnfs/
# cd /mnt_freebsdnfs/
# ls -la
ls: reading directory '.': Input/output error
total 0
# cd all
# ls -la
ls: reading directory '.': Input/output error
total 0

It looks that the Input/output error is caused by a NFS4ERR_NOFILEHANDLE

Is this setup correct, or is there a bug in the FreeBSD NFSv4.1 server?

Ced
-- 
Cedric Blancher <cedric.blancher@gmail.com>
[https://plus.google.com/u/0/+CedricBlancher/]
Institute Pasteur