[NFS-Ganesha-Devel] Question on empty ACL representation in the FSAL - issue with Ganesha 4.0

Hello, I am trying to upgrade our FSAL from ganesha 3.4 to 4.0.2 but I got into trouble regarding ACLs. It is not clear to me how an empty ACL should be represented / returned from the FSAL. Currently our FSAL implementation assigns NULL to fsal_attrlist.acl and the valid_mask with ATTR_ACL (getattrs). It seemed to work in 3.4 but in 4.0, nfs4_getfacl fails on a not supported error (on RHEL8, NFS4.0). I looked at some NFS traces, with ganesha 3.4 the response is ultimately translated to a a NFS_OK with the GETATTR attr_mask containing the ACL flag. In ganesha 4.0.2 the reply is NFS_OK but it doesn't contains any attr_mask. Does anyone know if it is a missuse of the FSAL API on our side ? What is the correct way to handle empty ACL ?