When creating an user from Perl API, allow parameter: change_password => 1
In file lib/Ravada/Auth/SQL.pm , at the sub add_user , accept the change_password parameter and insert it in the SQL like all the others there.
Also use it for creating the admin user in lib/Ravada.pm:
Ravada::Auth::SQL::add_user(
name => 'admin'
,password => 'admin'
,is_admin => 1
,change_password => 1
);