Cloned mac address for wired connection

I am trying to set up cloned mac address as stable for wired connection. The sys-net is an AppVM based on a template built using debian-12-minimal.

The bind-dirs is set up correctly and the file /etc/NetworkManager/conf.d/mac-random.conf is updated as below in the sys-net AppVM

[connection-mac-randomization]
ethernet.cloned-mac-address=stable

The below line in journalctl confirms that the config is picked up.

Jan 18 03:45:54 sys-net NetworkManager[<pid>]: <info>  [1705545954.0592] device (<eth>): set-hw-addr: set-cloned MAC address to <mac-address> (stable)

But the problem is that mac address is not consistent across reboots. My understanding is that the stable option should provide same mac address across reboots.

There is one more issue described below. However not sure if its related to the issue described above. There is no entry for the wired connection in /etc/NetworkManager/system-connections/. So, I open the Edit Connections dialog, updated some details in the wired connection, click save and did not see any entry made in the system connections folder. The below line in the journalctl indicates why there is no entry in the system connections folder

Jan 18 01:24:46 sys-net NetworkManager[<pid>]: <info>  [1705537486.0702] audit: op="connection-update" uuid="<uuid>" name="Wired connection 1" pid=<pid> uid=1000 result="fail" reason="Insufficient privileges"

Any inputs on how can I get consistent MAC address across reboots?