Error msg : Found no $GroupID for users

[pvanos]

I'm running OTRS 3.3.10 on a CentOS 6.7 platform
Referring to a previous topic (nr 28813).
Problem:
I find many entries in /var/log/messages like :
[Error][Kernel::System::Group::GroupLookup][Line:151]: Found no $GroupID for users!

I already removed in Frontend::Customer the (only) entry 'users' in CustomerGroupAlwaysGroups, hit [Update],and even restarted services httpd and otrs, but the message keeps coming.
Another thing I noticed, the messages (also?) occur every time someone logs in to OTRS.

Additional info:

• in Groups, I have a valid entry named "users Group" (comment: Group for default access) which looks system-generated at installing OTRS. This group is only containing 1 agent : root@localhost (Admin OTRS)
• I do not see any group simply named "Users"
• In roles<->groups, I can see various roles assigned to the group "users Group".

However, we use the principle to assign roles directly to users, not to groups.
So I wonder how I can eliminate this link to the non-existing group users.
Or should/could I just rename existing group "users Group" into "users" to get rid of the error ?

[pvanos]

Only now I have had the chance to experiment on a newly created (updated from copy of OTRS3.3 production database) OTRS4 test machine.
So, what I did is simply renaming the group "users Group" into "users", via Admin > Agent Management > Groups

I was very happy to find out that any reference (in other settings) to this group apparently is also dynamically renamed.