Cached AMP pages break on WPT lighthouse test

Running WPT against pages in the Google AMP cache. We use a private instance of WPT. Our tests started failing on 26th July.

this is an example page we test against:

I’ve attached a screen shot of the results I get on our private instance

I also ran a test on public WPT and got slightly different but still bad results

The page is fine and the regular WPT tool gives normal results.

thanks in advance for any help


A bit more information. The breakage of the Lighthouse tests against Cached AMP pages started when our private instance of WPT started to use Lighthouse 5.2.0

More investigation it seems this is an issue with lighthouse 5.2.0 that others have seen.

A PR is here which may fix it.