Full video of what shows a Nokia feature phone running Android 8.1 has now emerged. The unknown Nokia feature phone prototype is not running KaiOS and rather one can clearly notice Android 8.1 mentioned in the system settings.
Google has been rumored to be working on an Android OS version tailored for feature phones. It may be the same Android version being tested on a Nokia feature phone. This video was posted on twitter.
Currently, it is not known what is the status of the Android feature-phone OS but Google has invested in KaiOS recently.