selenium: incorrect 'unexpected response, code=404' when manipulating DOM elements with Safari using ruby selenium-webdriver 3 beta4

Sites load with Safari, but driver always reports response code 404 when trying to manipulate the site.

w = Watir::Browser.new :safari
 => #<Watir::Browser:0x7f985ddd94f371e6 url="" title="">
w.goto "http://google.com"
 => "http://google.com"
w.text_field(:id => "lst-ib").when_present.set("some data")
Selenium::WebDriver::Error::WebDriverError: unexpected response, code=404, content-type=""
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/selenium-webdriver-3.0.0.beta4.0/lib/selenium/webdriver/remote/http/common.rb:88:in `create_response'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/selenium-webdriver-3.0.0.beta4.0/lib/selenium/webdriver/remote/http/default.rb:86:in `request'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/selenium-webdriver-3.0.0.beta4.0/lib/selenium/webdriver/remote/http/common.rb:59:in `call'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/selenium-webdriver-3.0.0.beta4.0/lib/selenium/webdriver/remote/bridge.rb:653:in `raw_execute'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/selenium-webdriver-3.0.0.beta4.0/lib/selenium/webdriver/remote/bridge.rb:631:in `execute'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/selenium-webdriver-3.0.0.beta4.0/lib/selenium/webdriver/remote/bridge.rb:579:in `element_displayed?'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/selenium-webdriver-3.0.0.beta4.0/lib/selenium/webdriver/common/element.rb:191:in `displayed?'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/elements/element.rb:403:in `block in visible?'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/elements/element.rb:621:in `element_call'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/elements/element.rb:403:in `visible?'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/elements/element.rb:425:in `present?'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/wait.rb:136:in `wait_until'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/wait.rb:114:in `block in method_missing'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/wait.rb:41:in `block in until'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/wait.rb:78:in `block in run_with_timer'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/wait/timer.rb:14:in `wait'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/wait.rb:77:in `run_with_timer'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/wait.rb:40:in `until'
    from /Users/samuel.nissen/.rvm/gems/ruby-2.3.1/gems/watir-webdriver-0.9.3/lib/watir-webdriver/wait.rb:114:in `method_missing'
    from (irb):5
    from /Users/samuel.nissen/.rvm/rubies/ruby-2.3.1/bin/irb:11:in `<main>'

macOS Sierra 10.12 ruby 2.3.1 selenium-webdriver 3.0.0.beta4.0 Safari 10.0