Firefox E10S issues

When E10S (multi-process) in enabled in Firefox Nightly, some websites don't work correctly. For example, if HTTPS Everywhere is enabled AND E10S is enabled in Nightly options, duckduckgo.com settings can't be accessed. If you're at the website, and click on settings, instead of going to the settings page, all you see is "301 Moved Permanently" in bold print with "nginx" in small print underneath. If I disable HTTPS Everywhere, I can access the settings page for duckduckgo.com without any issues. This has happened for multiple other sites.

This website, https://trac.torproject.org/projects/tor/report/19, which I got the link from the eff web page, does not work with HTTPS Everywhere and E10S on at the same time; in this case, a completely blank page opens up.

For what it's worth, Disconnect and DoNotTrack also seem to malfunction when E10S is running.