database vault does not prevent already given privileges

Hi,

we have  a  database vault enabled  database  version 19.6 .   There is a  realm  to protect a schema objects.  i will explain my problem  with an example :

The  Schema is   Schema1 .   There is a realm as  for Schema1

Schema1  has  a table as table1.   there is a role  as schema1_ro_role.  and this role  granted  for schema1.table1

The users  granted  schema1_ro_role    can  select   schema1.table1    .   The realm  does not  prevent  this select.

Is it  normal ?  What can i do  to prevent  accessing   users  select for this table   ?

Regards