Ever see a chart in your page experience report or core web vitals reports that shows core web vitals data and then doesn't and then does again? If you do, you are not alone, it means you are "teetering on the edge of having enough field data for evaluating the CWV properly," John Mueller of Google said.
Here is a chart from Theo Burtis showing this:
Theo asked "do you have any thoughts on why these fluctuations are happening? Doesn't correlate with CWV data or overall engagement data, and can't replicate on other domains."
John responded "My guess is your site is teetering on the edge of having enough field data for evaluating the CWV properly - sometimes it's enough, sometimes not. I wouldn't worry about it."
My guess is your site is teetering on the edge of having enough field data for evaluating the CWV properly - sometimes it's enough, sometimes not. I wouldn't worry about it.
— 🧀 John 🧀 (@JohnMu) November 12, 2021
Google's teetering data is fun, when it comes to CWV data or being on the edge of indexing or edge of quality.
Forum discussion at Twitter.