Postgres not using correct indices for views.

Hi,

we have created restricted view for our tables, so that we can allow 
access to non-gdpr relevant data but hide everything else.

For exactly those views, the Query Planner uses the wrong indices, when 
executing exactly the same query, once it takes 0.1 s and on the views 
it takes nearly 18 sec (it does a full table scan, or uses the wrong 
indices).

Do we have to GRANT additional rights? I see it's using some indices, 
just not the correct ones!

Has anyone experienced the same issues? What can we do about that?

Thanks
BR
Thomas