GitLab Omniauth "omniauth_external_providers" option

Dear all / GitLab community support,

I’ve been using GitLab CE version for software projects and code repository management and it’s great to use.

Recently I try the Onmiauth modules for OAuth login and works well. However, I hit an uncertainty about the gitlab_rails[‘omniauth_external_providers’] option.
It is used to define users of OAuth registered and logged in to be External by default. Then the admin can gradually granted them relevant permissions along.

However I noticed that after setting new permissions, if the user logs out and re-logs in then any configured permissions will be gone and re-initialized as simple External users (like being reset).
Is this behaviour normal? In case, is it possible to preserve Omniauth users’ permissions after re-logging?

Thank you very much!

Best Regards,