Every now and then the XO and XOA can not umount the remotes at powerdown/reboot but they will shut down after a time out of 2-3 minutes

I have 2 remotes, NFS with option hard on a QNAP and SMB on a TrueNAS scale. Seems like both fail the umount.
Same on XOA 5.99.1 and XO latest ba375 from source (docs not script).

If I ls a mount point, I get this
ph7@XO:/run/xo-server/mounts/0927f4dc-4476-4ac3-959a-bc37e85956df$ ls xo-config-backups xo-pool-metadata-backups xo-vm-backups
If I do a ls -a, I also get a lot of .nfs00000000 and .keeper_ files, all 0 bytes and some are older than the existing backups. In an attempt to fix this, I manually deleted some old empty backups, so I guess the old ones origin from them.

I am running a Lenovo Thinkcentre mini PC with Ryzen 5 2400GE 16GB, XCP-ng 8.3 latest, upgraded from RC2 by ISO
The issue was also in RC2 and maybe RC1, I don´t remember.

Anybody got any idea where to look ?

Is there a way to change the SMB BR to NFS ??
Perhaps create a new NFS BR, copy all files, Connect to new NFS BR and forget the SMB BR. Is that possible ???