factory_girl + rspec doesn't seem to roll back changes after each example

Similar to the problem described here: http://rpheath.com/posts/411-how-to-use-factory-girl-with-rspec

in Short (shorten'd code):

spec_helper:

config.use_transactional_fixtures = true
config.use_instantiated_fixtures  = false

factories.rb:

Factory.define :state do
  f.name "NY"
end

in my spec

before(:each) do 
  @static_model = Factory(:state) # with validate uniqueness of state name
end

error:

duplicate entry name "NY" etc.

Question: Shouldn't rspec clear database before each spec example and hence not throwing duplicate entry errors?