The layout isn't shifting, so it's not a layout shift.

And it's not unexpected, because it comes from a css transition.

Sure.

It's just that the spirit of Google's core web vitals has been to measure the properties of a web page that have the most impact on users. How quickly content appears on a page, how visually stable the content is, and how long it takes the page to respond to an interaction.

In the case of this page, I don't think it can be considered visually stable at all in the first second after it's loaded.

And yet, core web vitals cannot demonstrate this.