7.1/Master: Not affected.
Steps to reproduce:
1) Start a 7.0 bundle
2) Log in as Admin on latest IE11 on Windows 10
3) Enable and configure ReCaptcha by going to Configuration > Server Administration > CAPTCHA (You can get keys at https://www.google.com/recaptcha)
4) In Site Admin > Content, add a Form with on text field and enable ReCaptcha for this Form. (Edit > three-points > Settings > Require captcha)
5) Add a Form portlet to the Welcome page and selected the form created in step 2
6) Reload page.
7) Click on "I'm not a robot"
Expected: Checkmark to appear
Actual behavior: Spinner loads indefinitely