The KDE Network Monitor requires 3 reboots before being able to connect to wireless network.

After installing 11.4, I need to type in the command to update the firmware for a broadcom wifi adapter. Then I needed to reboot, twice, before the system knew to use the adapter (where the adapter wifi light goes from orange to blue).

Then I needed to add my wireless network and type in my key. But the key does not take. If I click on my wireless network icon, it just re-asks for the key and does not connect nor give any other message. Network icon continues to display no connection.

So I need to reboot again.

When the system starts again, the adapter is blue, I click on the icon for my wifi network and it connects without asking for my key and I can then set to start my wifi by default.

Now my wifi works fine.

Just a “me too.”
Mine was a fresh 11.4 NET install with the LXDE desktop on a dv9500 laptop which has been running 11.3 (so I know that the iwlagn network device driver works).
I wasn’t sure whether the problem was specific to my setup, curiously during the Stage 1 Install wireless was recognized and working fine (network settings weren’t preserved for Stage 2 but that’s another story).

Although connecting to an open AP wasn’t an issue, the first time I connected to a secured AP I ran into what the OP describes, but didn’t reboot, but did switch my network card off/on (my laptop has that hardware feature), whereupon Network Manager then accepted settings prompting for new credentials for a new keyring to store the AP passphrase (this appears to be specific to LXDE and likely shouldn’t be seen in KDE or Gnome).

FWIW,
Tony