Missing required Core Web Vitals metric(s)

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I get the following message when running Google Page Speed Insights for a page:

Field Data - Over the previous 28-day collection period, field data shows that this page cannot be assessed due to missing required Core Web Vitals metric(s).

I also note that two of the fields in PSI are greyed out for this page, as per this screenshot:

PSI Field Data - greyed out fields

However the Lab Data section of PSI shows all the relevant metrics, so it's clear the page is accessible as per this screenshot:

PSI Lab Data

Does anyone know what could be causing the "page cannot be assessed" message and greying out of certain metrics? Please note that the page has always had sufficient traffic to generate field data in PSI.

Thanks

core-web-vitals pagespeed-insights
1 Answers

That message gets shown if there's not enough data and it it can fluctuate over time - for example, if there was more site traffic during one 28-day period than another. It's not uncommon to see data for LCP & FCP but not FID. FID can only be measured if the user interacts with the page, and that doesn't always happen on every page load. However, seeing a lack of data for CLS (when there's sufficient LCP & FCP data) is unusual and not expected.

user_161666670
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