Password Protected content exposed on other browsers and machines

Hi
I have password protected some content on a page with the shortcode [protect password="xyz"]content[/protect]
It seemed to work but now that I have entered the password to reveal the content it is now revealed on other browsers and also on other machines in the office.
Is this normal?
Looking on Google I wonder if it is a cache thing? I use WP Rocket.
thanks
Mariette