Encountered the following in my cron jobs that run WPT (snipped):

diff --git a/webrtc/RTCPeerConnection-generateCertificate.html.txt b/webrtc/RTCPeerConnection-generateCertificate.html.txt

-FAIL generateCertificate() with valid expires parameter should succeed assert_approx_equals: expected 1530319997005 +/- 1000 but got 1530319996000
+PASS generateCertificate() with valid expires parameter should succeed

This may indicate a verification range that's too narrow, leading to spurious test failures.

Not high priority, but noted in order to remember.