SCALE Samba ACLs broken for Mac clients

I have a multi-user smb/afp share in SCALE, where i set ACLs so that all users within a group can write to it, and expect the newly created files/directories to inherit the share's group

{code}
 

movi@truenas:/mnt/VMPool/Media$ getfacl .

# file: .

# owner: root

# group: Media

user::rwx

group::rwx

other::---

default:user::rwx

default:group::rwx

default:other::---
{code}

However, this does not work for Mac SMB clients, the default group ACL is ignored, and files and directories are created with the users primary group. This is in contrast to CORE where the exact same setup works perfectly.
The problem is with that on linux, the share uses acl_xattr as the vfs object for storing ACLs, and this module forces force unknown acl user = true, which is the culprit.