Hello @SivaRamaKrishnaNV @VickNV
After multiple trials and tests, I managed to find the root cause its due to
sudo apt-get upgrade
By default the Ubunutu software updater is set to download and install security updates daily. This explains why I was only seeing issues after an overnight period. I still don’t know why things go awry when an security upgrade is done, and would request Nvidia to investigate.
For those looking to solve this issue :
After gdm3/lightdm install , go to the software updater settings as shown below:
Once the settings window opens from change the default settings to the one shown below:
For now not installing the upgrades works , so don’t install the security/recommended upgrades.