We have a private instance set up, and noticed that as of 4 days ago (Feb 20, 2020) we stopped getting Speed Index data. I believe the problem is no Start Render is being calculated, so it cannot calculate the rest of the associated visual-based metrics, including time to interactive.
I was hoping this was isolated to our instance, but it’s happening on public webpagetest.org too. Here’s an example from just now (I tried on a few locations too):
I’ve tried to figure out what changed, and I do not see anything obvious. Compared to results that were working a few days prior, the Chrome user agent is identical, the webpagetest version is the same, video flag is still being passed…I’m out of ideas.
I’m glad this is easy to replicate…but don’t see a solution here. Anyone have any ideas?