Running the 'id user' command on a Unix client does not correctly return all of the group information for that user.
You are not using the correct format for the 'id' command to return the data you want.
To verify the proper format of the 'id' command to use:
(1) Enter 'which id' to see the 'id' that is being called by default.
-- If the default 'id' is '/usr/bin/id' then to see all groups, use the format: 'id -a <username>'
-- If the default 'id' is '/usr/xpg4/bin/id' then by default you should be seeing all groups.