We are seeing an interesting issue with a specific site when it is being tested on WebPageTest in Chrome but only when the connection is traffic-shaped to slow it down. IE and Firefox don't have similar issues.

The status message will get stuck with a "Processing request" message and won't proceed any further.  The actual request it gets stuck on (at least the last message in the Network.* log of messages) changes.

The trace and netlog don't show anything suspicious and connecting a debugger to Chrome after it is in this state shows all of the threads in the renderer and browser process sitting in their various run loops waiting for messages (i.e. idle).

It's possible that it is tied to remote debug protocol and some interaction but even disabling everything except for Page.* interactions doesn't make it go away (but testing manually without remote debug connected in the same environment doesn't trigger it - even loading in a separate tab in the same session).

Github Issue with some of the discussion is here: https://github.com/WPO-Foundation/webpagetest/issues/877

Test result with trace and netlog is here: https://www.webpagetest.org/result/170517_BT_f762002e35781ff9ed6c90924329e68b/