Cloudflare tunnel generates dangerous site warnings from Google

I created a Zero Trust tunnel and application/policy for it. It all worked as expected, allowing me to access my local machine via ssh-in-browser. However, a few days later, Chrome/Google began marking my site as dangerous with a big red warning and extra click to proceed to the site. Why is this warning appearing?

Is the warning expected given that Cloudflare tunnel is in fact a man-in-the-middle of my secure connection to my site?

What are the steps to confirm there are no issues and remove this warning?