Here is my experience, As @pidigo9280 mentioned, I’m too a user of night light frequently, I never turn it off, however on certain instances, such as unlocking a app with fingerprint, and on lockscreen, the nightlight seems to be disabled for a brief moment. however the same does not happen when there a guest mode or a additional user mode is used.
As a Nothing 2A user this experience is causing bad experience I understand this is a new model may come with new bugs and improvements will be made as time goes by, but please do consider having this post checked and get a fix for this via an update as soon as possible.