With fission.autostart enabled, if I click on a bugzilla link from gmail, it renders an unformatted page. Attached is a screenshot of that unformatted page. Also, the URL bar still shows "https://mail.google.com/mail/u/0/" instead of the bugzilla URL.

Also, once on that page, clicking on any hyperlink returns 404, which may need to be tracked separately.

Seeing the same behavior with other links that are clicked on from within a Gmail message. Also, in the page the opens after clicking the link in Gmail, all clickable links are using "https://mail.google.com/mail/u/0/" as the root.

Is this a rendering issue? I saw a warning when I open a link from Gmail;

WARNING: CompleteRedirectSetup failed, HttpChannelChild already open?: file /home/hiro/central/netwerk/protocol/http/HttpChannelChild.cpp, line 2125

Agreed, this is virtually certainly an issue with the way that the page is loaded. I.e. either DOM or networking. Tentatively moving to DOM.

The component has been changed since the priority was decided, so we're resetting it.
For more information, please visit auto_nag documentation.

(In reply to Hiroyuki Ikezoe (:hiro) from comment #2)

Is this a rendering issue? I saw a warning when I open a link from Gmail;

WARNING: CompleteRedirectSetup failed, HttpChannelChild already open?: file /home/hiro/central/netwerk/protocol/http/HttpChannelChild.cpp, line 2125

FWIW, when I try to open https://mana.mozilla.org/, I see the same warning, and I can't open the site at all, I see "Nightly has just been updated in the background. Click Restart Nightly to complete the update.", pretty weird message. :)

Redirection breaking sites is the biggest and most frequent issue I have encountered since enabling fission.

I posted a patch in bug 1561089 that fixes this issue.