fieldsets FULL doesn't return all member fields

I have a field in a custom registration form that I don’t want to show on the member profile page because I don’t want the member to be able to change the value after registration.
If I remove the field from the member profile, it is still visible in the dashboard data for the member but is not returned when I call CurrentMember.getMember with fieldsets = FULL.
The documentation says that “FULL” returns all fields but it does not! And I don’t see anyway to resolve this.
Please help!

Can someone from Wix please comment on this!? Is this expected behavior, or a bug? THIS IS A BIG PROBLEM FOR ME