Time to First Byte reported as 0 ms in LCP Breakdown #16861
Description
FAQ
- Yes, my issue is not about variability or throttling.
- Yes, my issue is not about a specific accessibility audit (file with axe-core instead).
- Yes, my issue is not answered by other FAQs.
URL
What happened?
I ran a Pagespeed Insight test on four different websites to analyze TTFB. I noticed that in the LCP Breakdown section, the subpart “Time to First Byte” is always reported as 0 ms (!)
This occurs for all four websites tested, even though a measurable server latency is clearly shown in the “Document request latency” section.
What did you expect?
It says 0ms for both mobile and desktop by the way
Mobile : 
Desktop: 
Here is a screenshot showing server latency :
What have you tried?
I tested this on four to five different websites, on both mobile and desktop, and the value is always reported as 0 ms.
How were you running Lighthouse?
PageSpeed Insights
Lighthouse Version
n/a
Chrome Version
Version 144.0.7559.60 (Build officiel) (64 bits)
Node Version
No response
OS
Windows
Relevant log output
https://pagespeed.web.dev/analysis/https-www-eskimoz-fr/vd1d6ggpde?form_factor=mobile