I think its related to
https://lists.samba.org/archive/samba/2016-September/202918.html
I am not very competent at Bugzilla. I scanned the list on
https://bugzilla.samba.org/buglist.cgi?quicksearch=windows%2010 and I
couldn't find one I could track for this problem to be fixed.
I filed an issue upon https://bugs.archlinux.org/task/50847 since I use Arch.
I will try and provide a tcpdump if no one else has done it during the
weekend. Otherwise, please let me know how to track the regression!
Many thanks,