Sorry to read that. NS8 uses plain vanilla samba and it seems to work generally as there were no other join issues in the forum: Search results for 'join order:latest' - NethServer Community
So I’m convinced the issue can be fixed.
I’m going to test it using Win 24H2 and report…
Do you still use the NS8 itself as DNS server in /etc/resolv.conf on the NS8? Please correct it to just use 1 DNS server that’s not the NS8 itself.