Double/Automatic Page Reloading
How to recreate: Go to https://duolingo.com Click Discussions Now click Spanish (or any other Discussion that haven't viewed yet) Watch the page refresh itself about 3-5 times.
Using latest Chrome Stable on latest Ubuntu.
In fact, quite a lot of the site doesn't work when you use https instead of http. For example the hover over a word then speech feature.
Hope you get it fixed soon :)