WPA Password Dialog not available

The iwlwifi module and drivers for the Intel 7260 are now included as part of the baseline LT4 21.2 release. After downloading the firmware for the 7260:

sudo apt-get install linux-firmware

and rebooting, wireless networks show up in the Network Manager as expected. However, if a WPA/WPA2 network is selected from the Network Manager, no dialog is presented asking for a password. Subsequently no network is selected. Non password protected open networks are connected to normally.

/var/log/syslog shows the following:

Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <info> Activation (wlan0/wireless): access point 'Kangaboxer Wi-Fi Network' has security, but secrets are required.
Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <info> (wlan0): device state change: config -> need-auth (reason 'none') [50 60 0]
Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <info> Activation (wlan0) Stage 2 of 5 (Device Configure) complete.
Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <warn> No agents were available for this request.
Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <info> (wlan0): device state change: need-auth -> failed (reason 'no-secrets') [60 120 7]
Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <info> Marking connection 'Kangaboxer Wi-Fi Network' invalid.
Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <warn> Activation (wlan0) failed for connection 'Kangaboxer Wi-Fi Network'
Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <info> (wlan0): device state change: failed -> disconnected (reason 'none') [120 30 0]
Jan 12 05:09:16 tegra-ubuntu NetworkManager[666]: <info> (wlan0): deactivating device (reason 'none') [0]

At times, there is a dialog box which says:

Connection failure
Connection activation failed
(1) Creating object for path '/org/freedesktop/NetworkManager/ActiveConnection/3' failed in libnm-glib.

The connection can be manually configured, and will work as expected so I don’t think it’s a driver issue per se.

modprobe remove and reinstall made no difference.

If I compile the iwlwifi modules from the kernel source and install them, things work as expected.

Does anybody know how to fix this so that it “works out of the box”?