That's somewhat in debate, the last I saw. The initial report was it affected a user using Firefox, and it didn't when they switched useragents. Since then, there have been reports of users not seeing it in Firefox, but seeing it in other (even chromium-based) browsers. So it seems likely they are A/B testing it, but less clear if they are intentionally targeting non-Chrome browsers.

Their goal, quite clearly, is to prevent (or at least heavily discourage) adblockers. This is one attempt to detect them, and maybe in Chrome they have a different detection mechanism so it doesn't show the same behavior.

It would be a particularly foolish move on their part to push Chrome by punishing everything else right now, while they are in the middle of multiple anti-trust lawsuits. It makes me think that is unlikely to be the intent of this change.