Stealth mode does not switch on at login

Read here: https://support.apple.com/guide/mac-help/use-stealth-mode-to-keep-your-mac-more-secure-mh17133/mac

If that doesn't work, I suggest you contact Apple support.

EB UK wrote:

It is a requirement of a company I work for that Mac users should have stealth mode switched on at all times (among other security requirements).

I have the Firewall in operation and I have ticked the box to Enable Stealth Mode and clicked the padlock to preserve the settings. It closes down when I log out and shut down but every time I start up again (at the beginning of the day) the Firewall is enabled, the padlock remains locked, yet Stealth Mode fails to enable. This is happening all the time.

What can I do to preserve the setting?

Am running MacBook Air and Big Sur 11.6.1

If you are using a VPN maybe it needs to be added to the allow list