Upgrade to 3.0 causing weird behavior - first request to google regional sites?

[shmilla]

We upgraded our private instances:
WPT 3.0
Agent 3.6.2
We currently host on Amazon (AWS).

We are seeing that the request which is to www.(customer name).com has the first request in WPT shown as a request to regional google sites. For example in tokyo we see the first request is
https://www.google.co.jp/
and some ireland tests show
https://www.google.ie/

what's weird is it's not all three runs, we see it on one or two, causing the median shifting to the skewed result.

[shmilla]

It turns out both my issues were related to some prewarming functionality in WPT for certain caches. It sounds like a race was lost and so we see the response late. Likely why we only saw it in our 3G tests. Patrick has, most awesomely, provided a patch