Claude's analysis: "it skips logged-in WordPress users (wordpress_logged_in_* cookie), skips /wp-admin and /wp-login.php, and rate-limits to once per day per visitor via localStorage. That's why site admins don't see it — and why you only saw it on first load."

Doing a bit of digging too - it also filters only to users running MacOS or Windows and skips everything else which is why it will be invisible to the devices I tried it on.