Filing this on behalf of a bug reporter on IRC. I have not actually confirmed the bug. The original bug reporter thinks this is related to bug 591654, but I don't know enough about Blink loading to make that judgement.
From the original bug reporter, with some light editing:
Reduced test case: https://burningchrome.com/~fnd/_/c43eca6e-2815-4059-aaaa-9f0366f6f779.html
To reproduce:
1. Open dev tools' network tab to see the requests
2. Navigate to the test case
Expected: Single request for bootstrap.min.css
Actual: There are two (seemingly) identical requests for bootstrap.min.css
Removing the <link> element's integrity attribute makes the duplicate request disappear. Tested with Chrome v60.0.3112.90 on OS X
Comment 1 by shrike@chromium.org
, Aug 10 2017