The last Flow IE10 runs against beta labs failed "Create new topic logged in.Add new Flow topic".
The reported failure in https://wmf.ci.cloudbees.com/view/flow/job/Flow-en.wikipedia.beta.wmflabs.org-internet-explorer-10/157/testReport/%28root%29/Create%20new%20topic%20logged%20in/Add_new_Flow_topic/ is something about
And the talk and contrib links are not visible
But if you watch the screencast https://saucelabs.com/jobs/d4e55826d29841aea42661ff8acdbea7 , things have gone wrong long before this: the user is NOT logged in! The test has "Given I am logged in" and the test does fill in the login form, but the Flow page still shows "Log in" in the top right instead of "Selenium user", and the newly created topic is authored by an anonymous IP.
The mediawiki_selenium gem's login_with() function must actually check the page displayed after submission (usually the Main_Page) for a successful login and clearly report if login failed. Currently it makes no checks to see if login succeeded.
As to how it failed, there doesn't seem to be any delay or waiting after visit(LoginPage).login_with(...) , so maybe the browser test jumped to visit FlowPage before the login page has gone through form submission, login to CentralAuth, redirect to login.wikimedia.org, setting loginwiki token cookie, redirect back to some success page, etc. that give the browser the info to assert that it is logged in on the next page it visits. I just did a beta labs login and it took 13 seconds, but the Sauce Labs movie jumped from the login form straight to the Flow page in less than a second.