User and group broken permissions

After both PC and NAS turned off during the night, I tried the following:

- removed credentials from windows, logoff and login to reset shares access permissions

- created a new test_user member of the group family as below

- the actual groups{members}: users{ja} - family{test_user, enfants, ma}

- created a share "test_share"

- test_share: user_owner: ja (r/w) - group_owner: users (r/w)

- test_share groups and users permissions: ja:r/w - admin:r/w - users:r/w - guest:0 - family:0 - test_user:0, enfants:0, ma:0

0 means no read access, that is cannot mount

Now, both under Windows and Android acces: all members of the family group has r/w permissions despite they should not even be able to mount as per their permissions

If I remove all permissions (no mount) from the group users, I can setup proper permissions for all members of the family group

If I revoke group_owner permissions, users of the group family loose their access whatever I select for them

There are also near similar reports in the forum, one of them here:

https://community.netgear.com/t5/Using-your-ReadyNAS/Group-permissions-taking-preference-over-user/m-p/1092604#U1092604

Here's the content of the samba.conf for share2: it sounds no issues in the file and no members of the family group are included

[share2]
  path = /data/share2
  comment = ""
  admin users = "+admin","Administrator"
  write list = "ja","@users","+admin","Administrator"
  valid users = "ja","@users","+admin","Administrator"
  follow symlinks = 1

 Please, some moderator/technician provide help to fix these permissions issues