Captive Portal, the session is never closed.

[WhiteTiger]

I'm wasting time trying to understand why the Captive Portal login page appears with a new session, but then it doesn't appear again.
I'm realizing that in reality the session is never closed and therefore that user continues to be able to access the VLAN without being asked for a login anymore. This also happens when I turn off and restart the PC.

Is that so? Is it wanted?

The list of C.P. sessions doesn't help, which is not updated and in some cases is empty.

The firewall was installed again from scratch with all the default options, while for the creation of the VLAN and the C.P. The official documentation pages were used, so no errors should have been entered.