From @philipwalton:
A command to quickly generate the faulty traces:
LANTERN_DEBUG=1 lighthouse "https://next.webpagetest.org/themetrictimes/index.php" --only-audits="modern-image-formats" --save-assets --throttlingMethod="devtools"
Either an issue with the graph generation, or the simulator. I think the former.
From @philipwalton:
A command to quickly generate the faulty traces:
Either an issue with the graph generation, or the simulator. I think the former.