selenium: Click button does not work after upgrade to selenium 2.48.0

Doing test automation on a Ember.js web application: I have a button which is covered by a <div> with a cooky notification. It looks something like this:

With Selenium 2.47.1 clicking on that button works as expected in Firefox. With Selenium 2.48.0 clicking this button does not work in Firefox, although there is no exception or error. It’s like selenium thinks that the click worked properly but actually the click had no effect. Here the Robot Framework log:

The structure of HTML is something like this:

<header>...</header>
<main>
  <div>
    ::before
    <form>
      <button>Last check</button>
    </form>
  ::after
  </div>
</main>
<div>
  <div class="cookie-notification">
    ::before
    <a href="http://...">Close</a>
    ::after
  </div>
</div>

Just for comparison - executing the same click with Selenium 2.47.1 in Chrome results in a WebDriverException:

Traceback (most recent call last):
  File "<string>", line 2, in click_button
  File "C:\Python27\lib\site-packages\Selenium2Library\keywords\keywordgroup.py", line 15, in _run_on_failure_decorator
    return method(*args, **kwargs)
  File "C:\Python27\lib\site-packages\Selenium2Library\keywords\_formelement.py", line 316, in click_button
    element.click()
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webelement.py", line 69, in click
    self._execute(Command.CLICK_ELEMENT)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webelement.py", line 448, in _execute
    return self._parent.execute(command, params)
  File "C:\Python27\lib\site-packages\Selenium2Library\webdrivermonkeypatches.py", line 11, in execute
    result = self._base_execute(driver_command, params)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\webdriver.py", line 196, in execute
    self.error_handler.check_response(response)
  File "C:\Python27\lib\site-packages\selenium\webdriver\remote\errorhandler.py", line 181, in check_response
    raise exception_class(message, screen, stacktrace)

System configuration I:

• Microsoft Windows 7 64 bit
• Firefox 41.0.2
• Selenium 2.47.1
• selenium2library 1.7.4
• Robot Framework 2.9.2 ==> click <button> works

System configuration II:

• same as configuration I but
• Google Ghrome Version 46.0.2490.80 m ==> click <button> does not work, WebDriverException

System configuration III:

• same as configuration I but
• Selenium 2.48.0 ==> click <button> does not work, no error/exception