Ruby Rails testing removes data when JS is enabled

When I have a test case written like this:

it "creates a slot" do
  expect(p = FactoryGirl.create(:position)).to be_valid()
  expect(p = FactoryGirl.create(:experience)).to be_valid()
  visit new_slot_path
  expect(page).to have_content("New Slot")
  fill_in "slot_name", :with => "Slot test"
  select p.position, from: "slot_position_id"
  click_link "Add Education Experience"
  select e.experience, from: "slot_slots_experiences_attributes_experience_id"
  click_button "Create Slot"
end

It cannot find the experience to add. How ever the exact same test written like this, the drop down for experience exists, but the other drop downs for position go missing.

it "creates a slot", :js => true do
      expect(p = FactoryGirl.create(:position)).to be_valid()
      expect(p = FactoryGirl.create(:experience)).to be_valid()
      visit new_slot_path
      expect(page).to have_content("New Slot")
      fill_in "slot_name", :with => "Slot test"
      select p.position, from: "slot_position_id"
      click_link "Add Education Experience"
      select e.experience, from: "slot_slots_experiences_attributes_experience_id"
      click_button "Create Slot"
    end