nullfs folder does not mount into nfs

Hello,

I have nfs service & tftp to boot my raspberry from network. Before update to truenas 12 I have everything is working fine. but after update I start to get a lot of problems.
1) i have tftpboot folder which i mount with nullfs to nfsboot folder.
the folder is mounted with init script. and mount a visible from truenas
then I export nfsboot folder, which is successfully mounted, but mounted folder is not visible.

truenas mount:
/mnt/Data/tftpboot/558e8211 on /mnt/Data/nfsboot/rby2-srv/boot (nullfs, local)

exports:
/mnt/Data/nfsboot -alldirs -maproot="root":"wheel"

after boot my raspberry I see my nfs filesystem, but boot folder is empty:
ls -al /boot/
total 27
drwxr-xr-x 2 root root 2 Jan 27 00:28 .
drwxr-xr-x 21 root root 21 Dec 3 01:49 ..

but from truenas I see all files in boot folder
Ed