An SEO professional was concerned about font loading issues (external fonts) that were causing CLS (a Core Web Vitals attribute called Cumulative Layout Shift).
Their question is a simple one: can fonts cause CLS issues?
John answered that yes, fonts can cause CLS issues. This is especially true when they have to be loaded from an external source.
He explained it thoroughly in this fashion:
If you’re using an external font file, that file has to be loaded. Then, depending on how your website displays the content, it’s possible that you display the version without the font file first, then the font loads, and this shifts the layout, which causes CLS issues.
John referenced this article on Google’s web.dev site, which explains how to solve font issues that are causing problems with CLS.
This happens at approximately the 6:39 mark in the video.