usermod overrides /etc/user_attr.d/file

We have multiple subsystems with corresponding authorizations defined in /etc/security/auth_attr.d/<various-files>.

Recently a new subsystem attempted to add an authorization to an account using usermod -A +<newauth>, which created an entry in /etc/user_attr.

That account already had authorizations granted by a specific /etc/user_attr.d/file.

After the usermod -A +<auth>, the auths command only shows the new one.

Is that the intended behavior?

Would it be any different if the new one had been put in a different /etc/security/auth_attr.d/files2?

Or, to state the question as a business problem...