Thanks for your concern.
We never claim to declare the rpmb in the preset key as a valid rpmb key,
we add it as an example.
We don't really get reliable sources to get valid rpmb keys,
we only add features based on requests from users.
It would be great if you would share valid rpmb keys with us,
and we would be very glad to add them to the rpmb key preset menu and remove the invalid ones.
You can sent it to my gmail : firstname.lastname@example.org