You're missing mention of two groups that are DEFAULT gmod groups, admin and superadmin, case sensitive, that often inherit down a chain.
How are Owner, HA, Admins set up in the inheritance tree related to what is 'normal' expectation of ULib and Gmod where superadmin > admin > user (though, as an example "custom" group, we do add "operator")
Though it is possible to set up split group branches, it's an exacting science requiring experience with knowing how group inheritance works.
Can Target setups require proper inheritance set up.