title: Capybara auto revisit the same URL/null
body: <p>my test is simple. but this is failing <code>Capybara::ElementNotFound: Unable to find css ".cards"</code></p>
  
  <pre class="lang-rb prettyprint-override"><code>test "it renders region's species" do
      # ... insert test data to db in here
  
      visit "/regions/galaxy"
      within(".cards") do
        assert_selector(".card", count: 3)
      end
  end
  </code></pre>
  
  <p>in log I can see a everything is good except there is a second visit to <code>"/regions/null"</code>.
  this can of course render a blank page.
  how can this 2nd visit happen with "galaxy" replaced from null?</p>
  
  <p>this worked fine for a long time. suddenly its failing.
  I test by increasing <code>default_max_wait_time</code>but still same.</p>